An Online Resident-as-Teacher Curriculum Improves First-Year Residents' Self-Confidence Teaching in the Clinical Learning Environment.

We implemented an online Resident-as-Teacher curriculum for all incoming residents (PGY1s) to provide them with a basic foundation for effective teaching in the clinical learning environment. The curriculum consisted of 5 asynchronous modules delivered via the web from 2017-2021. Prior to starting the course, the PGY1s completed a self-assessment of their teaching ability (pre-test) and then again 7-8 months after completing the course (post-test). Analysis of the paired data from 421 PGY1s showed a statistically significant improvement in the self-ratings of their teaching from pre-test to post-test (p < 0.001). Our findings suggest that an online Resident-as-Teacher curriculum can produce lasting benefits in new residents' self-confidence as educators.

Do the benefits continue? Long term impacts of the Anatomy Education Research Institute (AERI) 2017.

BACKGROUND: The Anatomy Education Research Institute (AERI) was held in Bloomington, Indiana in July of 2017. Previous research has shown that AERI was successful in meeting Kirkpatrick's first two levels of evaluation via positive initial reactions and learning gains identified at the end of AERI. This manuscript demonstrates continued success in Kirkpatrick levels two and three via six-month and thirty-month follow-up surveys and nine-month follow-up focus groups and interviews. METHODS: Quantitative analyses were completed using Microsoft Excel (2019) and SPSS version 26 while qualitative analyses were completed for both survey responses and focus groups/interviews using thematic analyses. RESULTS: Results demonstrate that the learning gains seen immediately post-AERI 2017 were sustained for all participants (accepted applicants and invited speakers). Qualitative results continued to demonstrate positive reactions to AERI 2017. Both quantitative and qualitative results demonstrated that the main obstacle to educational research for most participants is time, while collaboration, IRB, institutional roadblocks, and devaluing of educational research were also identified as obstacles. CONCLUSIONS: The research presented here indicates positive outcomes to Kirkpatrick Levels 1, 2, & 3 of evaluation following AERI 2017. However, substantial obstacles still exist for researchers in medical education. The need for a sustained community of practice for educational researchers was suggested as a potential buffer against these obstacles and multiple options for providing that community are discussed.

Knowledge Gains and Changing Attitudes from the Anatomy Education Research Institute (AERI 2017): A Mixed Methods Analysis.

The inaugural Anatomy Education Research Institute (AERI 2017) was held in Bloomington, Indiana in July of 2017. This workshop style conference paired experienced educational researchers (invited speakers) with individuals interested in learning more about the field (accepted applicants). In 2017, AERI was held over a five-day period and entailed plenary style presentations, break-out sessions, and specific times for small group mentorship. All participants (applicants and invited speakers) completed a pre-conference survey at the beginning of the institute and a post-conference survey at the end of the institute. Both surveys included categorical and Likert scale questions as well as open-ended questions for participant feedback. Quantitative and qualitative analyses indicate that both applicants and speakers increased their knowledge of anatomy education research, but that additional obstacles remain. Funding, time, and a lack of respect for the field remain problematic for faculty that wish to complete educational research. Mentorship and a community of practice also emerged as major themes necessary for educational research to be successful.

What Does a Modern Anatomist Look like? Current Trends in the Training of Anatomy Educators.

Anatomical sciences are foundational to the health professions, yet little is known about the qualifications of anatomy educators at the graduate and professional level in the United States. Moreover, there is concern that the number of qualified anatomy educators being trained may be insufficient to meet the growing demand posed by new and expanded programs in medicine and allied health specialties. The authors surveyed anatomists from across the country to (i) characterize the educational credentials of current anatomy educators and (ii) assess the perceived need for education-focused postdoctoral positions or formal mentorships to prepare anatomists for teaching-intensive faculty positions. To probe the survey responses more deeply, one-on-one interviews were conducted with eight individuals selected to represent a diverse sample of respondents in terms of institution, gender, and academic rank. Results indicate that 30-40% of educators at the graduate level and approximately 60% of those at the undergraduate level lack graduate coursework in histology, embryology, and neuroanatomy. Forty-five percent of respondents had completed a postdoctoral fellowship. Eighty-six percent replied "yes/maybe" to the question of whether an anatomy education postdoctoral fellowship would benefit doctoral graduates. The top 3 reasons for this recommendation were to (i) establish independent educational research, (ii) improve a publication record, and (iii) gain additional teaching experience. Notable weaknesses of education-focused postdoctoral training were related to finances, fear of exploitation, and undervaluing of teaching. Moving forward, postdoctoral fellowships and other forms of postgraduate training may represent a key strategy for training anatomists in the current educational climate. Anat Sci Educ 00: 000-000. © 2018 American Association of Anatomists.

Development and Implementation of the Inaugural Anatomy Education Research Institute (AERI 2017).

Education research is increasingly being recognized as a legitimate route for faculty development in universities. However, many anatomy faculty lack the appropriate training and access to experienced mentors who can help them develop their own education research projects. Inspired by the American Physiological Society's Institute for Teaching and Learning, the coauthors proposed and developed the inaugural Anatomy Education Research Institute (AERI 2017). Funded by an American Association of Anatomists Innovations grant, the five-day institute was held in Bloomington, Indiana in July 2017. The coauthors spent two years preparing the conference schedule, inviting speakers who could discuss education research topics and mentor applicants, reviewing applications, developing assessment instruments for the institute, and hosting the institute. A total of 62 registered participants (applicants and invited speakers) attended AERI 2017. Through a series of presentations and workshops, participants were introduced to many aspects of education research and the Scholarship of Teaching and Learning, including developing rigorous education research questions, determining appropriate methods to assess these questions, and searching the education research literature. Each day also included regular time devoted to work on their own education research project with help from more experienced mentors. Throughout the conference, participants were encouraged to post information on Twitter, using the hashtag #AERI2017. Participants had strong positive impressions of the conference and strongly requested future AERI conferences be held. Follow-up analyses will assess the institute in alignment with Kirkpatrick's Four Levels of Evaluation Model, though preliminary evaluation indicates AERI 2017 met the original aims of the proposal.

The Association Between Peer and Self-Assessments and Professionalism Lapses Among Medical Students.

Peer and self-assessments are widely used to assess professionalism during medical school as part of a multisource feedback model. The purpose of this study was to examine the associations between peer and self-assessments and professionalism lapses at a large medical school. A retrospective case-control study design was used to compare peer and self-assessment scores from Years 1 to 3 of medical school for students who had been cited for professionalism lapses during medical school (case group; n = 78) with those of a randomly selected control group ( n = 230). Students in the case group had significantly lower peer assessment scores than students in the control group during all 3 years. Year 3 peer assessment scores showed the greatest difference (cases = 7.81 ± 0.65, controls = 8.22 ± 0.34, p < .01). Students with lower peer assessment scores were also significantly more likely to have been cited for a professionalism lapse (odds ratio = 6.25, 95% CI [3.13, 11.11], p < .01). This study reinforces the value of peer assessments of professionalism, which may be useful to help identify students who may be at risk for professionalism lapses during medical school.

Meta-analysis and review of learner performance and preference: virtual versus optical microscopy.

CONTEXT: Over nearly two decades, a wealth of literature describing the various capabilities, uses and adaptations of virtual microscopy (VM) has been published. Many studies have investigated the effects on and benefits to student learning of VM compared with optical microscopy (OM). OBJECTIVES: This study statistically aggregated the findings of multiple comparative studies through a meta-analysis in order to summarise and substantiate the pedagogical efficacy of teaching with VM. METHODS: Using predefined eligibility criteria, teams of paired researchers screened the titles and abstracts of VM studies retrieved from seven different databases. After two rounds of screening, numerical and thematic data were extracted from the eligible studies for analysis. A summary effect size and estimate of heterogeneity were calculated to determine the effects of VM on learner performance and the amount of variance between studies, respectively. Trends in student perceptions were also analysed and reported. RESULTS: Of the 725 records screened, 72 studies underwent full-text review. In total, 12 studies were viable for meta-analysis and additional studies were reviewed to extract themes relating to learners' perceptions of VM. The meta-analysis detected a small yet significant positive effect on learner performance (standardised mean difference 0.28, 95% confidence interval 0.09-0.47; p = 0.003), indicating that learners experience marked knowledge gains when exposed to VM over OM. Variation among studies was evident as high heterogeneity was reported. An analysis of trends in learner perceptions noted that respondents favoured VM over OM by a large margin. CONCLUSIONS: Although many individual studies have reported non-significant findings in comparisons of VM and OM, the enhanced power afforded by meta-analysis revealed that the pedagogical approach of VM is modestly superior to that of OM and is preferred by learners.

Is Reflective Ability Associated With Professionalism Lapses During Medical School?

PURPOSE: Recently, many have argued that learning to reflect on one's experiences is a critical component of professional identity formation and of professionalism. However, little empirical evidence exists to support this claim. This study explored the association between reflective ability and professionalism lapses among medical students. METHOD: The authors conducted a retrospective case-control study of all students who matriculated at Indiana University School of Medicine from 2001 to 2009. The case group (n = 70) included those students who had been cited for a professionalism lapse during medical school; the students in the control group (n = 230) were randomly selected from the students who had not been cited for a professionalism lapse. Students' professionalism journal entries were scored using a validated rubric to assess reflective ability. Mean reflection scores were compared across groups using t tests, and logistic regression analysis was used to assess the relationship between reflective ability and professionalism lapses. RESULTS: Reflection scores for students in the case group (2.46 ± 1.05) were significantly lower than those for students in the control group (2.82 ± 0.83) (P = .01). A lower reflection score was associated with an increased likelihood that the student had been cited for a professionalism lapse (odds ratio = 1.56; P < .01). CONCLUSIONS: This study revealed a significant relationship between reflective ability and professionalism, although further study is needed to draw any conclusions regarding causation. These findings provide quantitative evidence to support current anecdotal claims about the relationship between reflection and professionalism.

How the distinctive cultures of osteopathic and allopathic medical schools affect the careers, perceptions, and institutional efforts of their anatomy faculties: A qualitative case study of two schools.

Anatomy faculties are integral to basic science instruction in medical schools, particularly given the preponderance of anatomic instruction in the preclinical curriculum. Recent years have witnessed major curricular restructuring and other emerging national trends that pose significant challenges to anatomists. An examination of anatomy faculty perceptions at two philosophically distinct medical schools within this shifting climate provides an indicator of how different institutional characteristics may impact anatomy instruction and other faculty responsibilities. Semistructured interviews of anatomy faculty from a large, well-established allopathic medical school (Indiana University School of Medicine) and a small, new osteopathic medical school (Marian University College of Osteopathic Medicine) were explored using qualitative thematic analysis. Four overarching themes were identified: (1) Institutional philosophies, such as affiliation with osteopathic versus allopathic medicine, have minimal impact on how the anatomical sciences are taught. (2) Differences in anatomy faculty experiences at these two institutions are largely driven by the institution's size and history. There is a disparity between institutions in the relative importance of teaching and research, but an ability to do research is important for both faculties. (3) Anatomy instruction and research agendas are driven by personal philosophies and interests rather than institutional philosophy. (4) Autonomy is highly valued by anatomists at both institutions. All the participants share a devotion to educating future physicians. In fact, this study identified more similarities than differences in these two faculties. Finally, we argue that shared educational resources and research collaborations can improve anatomy education and faculty development at both institutions. Anat Sci Educ 9: 255-264. © 2015 American Association of Anatomists.

Understanding the current anatomical competence landscape: Comparing perceptions of program directors, residents, and fourth-year medical students.

A mixed methods survey of fourth-year medical students, resident physicians, and residency program directors at the Indiana University School of Medicine gathered perceptions of anatomical competence-defined as the anatomical education necessary for effective clinical practice. The survey items explored numerous aspects of anatomical competence, including the most effective modes of instruction, perceptions of readiness for clinical practice, and specific suggestions for improving anatomical education during medical school and residency. The response rate was 46% for fourth-year medical students, 47% for residents (as graduates from 137 medical schools), and 71% for program directors. A majority of students and residents reported that their course in Gross Anatomy prepared them well for clinical practice; that cadaveric dissection was important in the early development of their anatomical competence; and that placing a greater emphasis on clinical relevance in medical school would have improved their anatomical competence even further. However, in terms of anatomical preparedness upon entering residency, the program directors rated their residents less prepared than the residents rated themselves. All three groups agreed that there is need for additional opportunities for anatomical educational during medical school and residency. Suggestions for improving anatomical education included the following: providing more opportunities for cadaveric dissection during medical school and residency; more consistent teaching of anatomy for clinical practice; more workshops that review anatomy; and better integration of anatomy with the teaching of other subjects during medical school. Anat Sci Educ 9: 307-318. © 2015 American Association of Anatomists.

Implementation of an education-focused PhD program in anatomy and cell biology at Indiana University: lessons learned and future challenges.

In 2008, the Indiana University School of Medicine, in collaboration with the School of Education, admitted its first student to a newly approved PhD program in Anatomy and Cell Biology focusing on educational research rather than biomedical research. The goal of the program is twofold: (1) to provide students with extensive training in all of the anatomical disciplines coupled with sufficient teaching experience to assume major educational responsibilities upon graduation and (2) to train students to conduct rigorous medical education research and other scholarly work necessary for promotion and tenure. The 90 credit hour curriculum consists of biomedical courses taught within the School of Medicine and education courses taught within the School of Education, including courses in health sciences pedagogy, curriculum development, learning theory, quantitative, and qualitative research methods, statistics, and electives. To date, 16 students have entered the program, seven have passed their qualifying examinations, and five have earned their PhD degrees. Four students have received national recognition for their educational research and four graduates have obtained faculty appointments. Going forward, we must adapt the program's biomedical course requirements to incorporate the new integrated curriculum of the medical school, and we must secure additional funding to support more students. Overcoming these challenges will enable us to continue producing a small but stable supply of doctoral-level anatomy educators for a growing academic market.

Impact of a competency-based curriculum on medical student advancement: a ten-year analysis.

BACKGROUND: In 1999, the Indiana University School of Medicine implemented a new curriculum based on the attainment of core competencies beyond medical knowledge. PURPOSE: The objective was to document how the Student Promotions Committee (SPC) has adjudicated students' competency-related deficiencies over the past decade. METHODS: Using SPC records, the authors determined the frequency of competency-related deficiencies reported to the SPC over time, the nature of those deficiencies, and how the deficiencies were remediated. For the purposes of this study, traditional knowledge-related deficiencies like course failures were excluded from analysis. RESULTS: From 1999 to 2009, 191 students (138 male, 53 female) were referred to the SPC for competency-related deficiencies in 8 performance domains involving communication, basic clinical skills, lifelong learning, self-awareness, social context, ethics, problem solving, and professionalism. By comparison, 1,090 students were referred to the SPC for knowledge-related deficiencies during this time. Collectively, the 191 students were cited for 317 separate competency-related deficiencies (M ± SD = 1.7 ± 1.3; range = 1-10). Of these 317 deficiencies, the most prevalent were in the competencies of professionalism (29.3%), basic clinical skills (28.4%), and self-awareness (17.7%). Each of the remaining competencies constituted less than 10% of the total. Successful remediation utilized 12 methods ranging from a simple warning letter to repeating the year under close monitoring. Remediation was unsuccessful for 17 students (8.9%) who were dismissed from medical school primarily due to unprofessional behaviors and poor self-awareness. CONCLUSIONS: Competency-related deficiencies can be identified and remediated in most cases, but deficiencies in professionalism and self-awareness are especially challenging.

Do personality differences between teachers and learners impact students' evaluations of a surgery clerkship?

OBJECTIVE: Historically, the surgery clerkship at the Indiana University School of Medicine (IUSM) has received poor evaluations from medical students, and the authors of this article hypothesized that this negative feedback may reflect, at least in part, inherent differences in the personality styles of the learners compared with those of the surgery teachers (faculty and residents). Differences between teachers and learners could impede effective communication and impact adversely students' perception of, and satisfaction with, the learning environment. The objective of this study was to compare the inherent personality styles of surgery teachers and medical students. DESIGN: Using the Myers-Briggs Type Indicator (MBTI) to assess personality styles, we administered the instrument to 154 teachers in the surgery department and to 1395 medical students. Aggregate MBTI data for teachers and learners were analyzed based on four dichotomous scales. Chi square tests of independence were performed to examine the relationship between teachers and learners on the MBTI scales. SETTING: The study was undertaken at IUSM, which has been engaged in a process of cultural change for over 10 years, in part to ensure that both the formal curriculum and the learning environment support the development of self-awareness and professionalism among our graduates. RESULTS: We found that teachers were similar to learners on the Introversion/Extraversion scale and dissimilar from learners on the three remaining scales: Sensing/Intuition scale (p < 0.008), Thinking/Feeling scale (p < 0.000), and the Judging/Perceiving scale (p < 0.022). CONCLUSIONS: These results suggest that differences in personality styles may affect the teacher-learner interaction during the surgery clerkship and may influence negatively students' perception of the learning environment.

The influence of regional basic science campuses on medical students' choice of specialty and practice location: a historical cohort study.

BACKGROUND: Indiana University School of Medicine (IUSM) employs eight regional basic science campuses, where half of the students complete their first two years of medical school. The other half complete all four years at the main campus in Indianapolis. The authors tested the hypothesis that training at regional campuses influences IUSM students to pursue primary care careers near the regional campuses they attended. METHODS: Medical school records for 2,487 graduates (classes of 1988-1997) were matched to the 2003 American Medical Association Physician Masterfile to identify the medical specialty and practice location of each graduate. Multivariate logistic regression was performed to assess the effect of regional campus attendance on students' choice of medical specialty and practice location, while simultaneously adjusting for several covariates thought to affect these career outcomes. RESULTS: Compared to Indianapolis students, those who attended a regional campus were somewhat more likely to be white, have parents with middle class occupations, and score slightly lower on the Medical College Admission Test. Any such differences were adjusted for in the regression models, which predicted that four of the regional campuses were significantly more likely than Indianapolis to produce family practitioners, and that five of the regional campuses were significantly more likely than the others to have former students practicing in the region. When analyzed collectively, attendance at any regional campus was a significant predictor of a primary care practice located outside the Indianapolis metropolitan area. CONCLUSION: Attending a regional campus for preclinical training appears to increase the likelihood of practicing primary care medicine in local communities.

Influence of hometown on family physicians' choice to practice in rural settings.

OBJECTIVE: This study examines the influence of a physician's hometown location on the choice of practice location, adjusting for confounding variables. METHODS: Medical school records for 2,487 Indiana University graduates (classes of 1988--1997) were matched to the American Medical Association's Masterfile data to identify the graduates' current practice locations and specialties. Urban influence codes were assigned to each county in Indiana for the purposes of defining metro or nonmetro locations. Physician practice locations were mapped using ArcGIS software. Chi-square tests, logistic regression, and analysis of variance were used to examine the influence of hometown on choice of practice location. RESULTS: Chi-square tests revealed significant associations between physician hometown and current practice location. Logistic regression, controlling for age and gender, predicted physicians (all specialties) from nonmetro hometowns were 4.7 times as likely to locate their practice in a nonmetro location as compared to their peers from metro hometowns. Similarly, family physicians from nonmetro hometowns were 4.4 times as likely to choose a nonmetro practice location. There was not a significant difference in the mean distance between hometown and practice location for physicians from nonmetro hometowns compared to those from metro hometowns. CONCLUSIONS: This study underscores the influence of physicians' hometown on their choice of practice location.

Evaluating the quality of interaction between medical students and nurses in a large teaching hospital.

BACKGROUND: Effective health care depends on multidisciplinary collaboration and teamwork, yet little is known about how well medical students and nurses interact in the hospital environment, where physicians-in-training acquire their first experiences as members of the health care team. The objective of this study was to evaluate the quality of interaction between third-year medical students and nurses during clinical rotations. METHODS: We surveyed 268 Indiana University medical students and 175 nurses who worked at Indiana University Hospital, the School's chief clinical training site. The students had just completed their third year of training. The survey instrument consisted of 7 items that measured "relational coordination" among members of the health care team, and 9 items that measured psychological distress. RESULTS: Sixty-eight medical students (25.4%) and 99 nurses (56.6%) completed the survey. The relational coordination score (ranked 1 to 5, low to high), which provides an overall measure of interaction quality, showed that medical students interacted with residents the best (4.16) and with nurses the worst (2.98; p < 0.01). Conversely, nurses interacted with other nurses the best (4.36) and with medical students the worst (2.68; p < 0.01). Regarding measures of psychological distress (ranked 0 to 4, low to high), the interpersonal sensitivity score of medical students (1.56) was significantly greater than that of nurses (1.03; p < 0.01), whereas the hostility score of nurses (0.59) was significantly greater than that of medical students (0.39; p < 0.01). CONCLUSION: The quality of interaction between medical students and nurses during third-year clinical rotations is poor, which suggests that medical students are not receiving the sorts of educational experiences that promote optimal physician-nurse collaboration. Medical students and nurses experience different levels of psychological distress, which may adversely impact the quality of their interaction.

Status of complementary and alternative medicine in the osteopathic medical school curriculum.

Reflecting society's interest in complementary and alternative medicine (CAM), most allopathic medical schools in the United States offer instruction in CAM. Pertinent information about the teaching of CAM at osteopathic medical schools is lacking. The authors therefore sought to document the form and content of CAM instruction at osteopathic medical schools and compare their findings with those reported for allopathic medical schools in a recently published survey. Phone conversations with academic officials at each of the 19 colleges of osteopathic medicine revealed that only one school did not teach CAM. With the help of these officials, the authors identified 25 CAM instructors at 18 osteopathic medical schools and sent them questionnaires. All returned a completed form with details about CAM instruction at their schools. The authors found that CAM material was usually presented in required courses sponsored by clinical departments, was most likely taught in the first 2 years of medical school, and involved fewer than 20 contact hours of instruction. The topics most often taught were acupuncture (68%), herbs and botanicals (68%), spirituality (56%), dietary therapy (52%), and homeopathy (48%). Most (72%) CAM instructors were also practitioners of CAM modes of therapy. Few (12%) of the instructors taught CAM from an evidence-based perspective. The authors conclude that the form and content of CAM instruction at osteopathic medical schools is similar to that offered at allopathic medical schools and that both osteopathic and allopathic medical schools should strive to teach CAM with less advocacy and more reliance on evidence-based medicine.

A Family Day program enhances knowledge about medical school culture and necessary supports.

BACKGROUND: A Family Day program was implemented at Indiana University School of Medicine to educate the families and friends of in-coming medical students about the rigors of medical school and the factors that contribute to stress. METHODS: Surveys that assessed knowledge, beliefs, and attitudes about medical school were administered to participants before and after the program. RESULTS: After the program, participants showed a significant improvement in their understanding of medical school culture and the importance of support systems for medical students. Post-test scores improved by an average of 29% (P < 0.001) in each of the two years this program was administered. CONCLUSIONS: The inclusion of family members and other loved ones in pre-matriculation educational programs may serve to mitigate the stress associated with medical school by enhancing the students' social support systems.

The teaching of complementary and alternative medicine in U.S. medical schools: a survey of course directors.

PURPOSE: The number of U.S. medical schools offering courses in complementary and alternative medicine (CAM) has risen sharply in recent years. This study gauged the current state of CAM instruction by gathering details about the specific topics being taught and the objectives behind the instruction. METHOD: Data were collected from questionnaires mailed to 123 CAM course directors at 74 U.S. medical schools. RESULTS: Questionnaires were returned by 73 course directors at 53 schools. The topics most often being taught were acupuncture (76.7%), herbs and botanicals (69.9%), meditation and relaxation (65.8%), spirituality/faith/prayer (64.4%), chiropractic (60.3%), homeopathy (57.5%), and nutrition and diets (50.7%). The amounts of instructional time devoted to individual CAM topics varied widely, but most received about two contact hours. The "typical" CAM course was sponsored by a clinical department as an elective, was most likely to be taught in the first or fourth year of medical school, and had fewer than 20 contact hours of instruction. Most of the courses (78.1%) were taught by individuals identified as being CAM practitioners or prescribes of CAM therapies. Few of the courses (17.8%) emphasized a scientific approach to the evaluation of CAM effectiveness. CONCLUSION: A wide variety of topics are being taught in U.S. medical schools under the umbrella of CAM. For the most part, the instruction appears to be founded on the assumption that unconventional therapies are effective, but little scientific evidence is offered. This approach is questionable, especially since mainstream medicine owes much of its success to a foundation of established scientific principles.

Rapid changes in shape and number of MHC class II expressing cells in rat airways after Mycoplasma pulmonis infection.

Mycoplasma pulmonis infection in rodents causes a chronic inflammatory airway disease with a strong immunological component, leading to mucosal remodeling and angiogenesis. We sought to determine the effect of this infection on the shape and number of dendritic cells and other major histocompatibility complex (MHC) class II expressing cells in the airway mucosa of Wistar rats. Changes in the shape of subepithelial OX6 (anti-MHC class II)-immunoreactive cells were evident in the tracheal mucosa 2 days after intranasal inoculation with M. pulmonis. By 1 week, the shape of the cells had changed from stellate to rounded (mean shape index increased from 0.42 to 0.77). The number of OX6-positive cells was increased 6-fold at 1 week and 16-fold at 4 weeks. Coincident with these changes, many columnar epithelial cells developed OX6 immunoreactivity, which was still present at 4 weeks. We conclude that M. pulmonis infection creates a potent immunologic stimulus that augments and transforms the OX6-immunoreactive cell population in the airways by changing the functional state of airway dendritic cells, initiating an influx of MHC class II expressing cells, and activating expression of MHC class II molecules by airway epithelial cells.