Autoimmune thyroid disease and ovarian hypofunction: a review of literature.

Thyroid hormones(THs) are essential for the proper functioning of the ovaries, and multiple studies have shown that thyroid abnormalities, especially during adolescence and reproductive age, can lead to lifelong ovarian dysfunction. Autoimmune thyroid disease (AITD), one of the most common organ specific autoimmune diseases, is mainly mediated by cellular autoimmune reactions, and has strong inflammatory infiltration and immune active cells, including chemokines and cytokines, which are important components of ovarian aging. This suggests that autoimmune and inflammatory molecular processes may play a role in the emergence of ovarian dysfunction. The purpose of this review is to summarize recent in vivo and in vitro evidence of a complex relationship between AITD and ovarian dysfunction. AITD is closely related to the decline of ovarian function from the perspective of antibody, cytokine, oxidative stress, and genetic factors. Finally, some of the currently known treatments for AITD and hypo ovarian disease are summarized.

IgG4-Related Disease of the Ovary.

Immunoglobulin G4-related disease is characterized by dense fibrosis, obliterative phlebitis, and lymphoplasmacytic infiltration that contains abundant IgG4 positive plasma cells. It causes tumefactive lesions in the involved organs and is most commonly seen in the salivary glands, pancreas, and retroperitoneum. Ovarian involvement has been reported in only two cases. In our case, a 58-year-old female patient presented with abdominal distention and pain. Pelvic computed tomography revealed a soft tissue lesion compatible with the omental cake, several intraabdominal implants, and bilateral adnexal fullness. A laparotomy was performed under suspicion of peritoneal carcinomatosis secondary to bilateral adnexal mass. In the histopathologic examination, abundant lymphoplasmacytic infiltration and dense fibrosis were observed in both ovaries and the peritoneum. In the areas of greatest density, the density of IgG4-positive plasma cells was found to range from 40 to 50 per high-power field. The patient was accepted as suffering from probable IgG4-related disease because of the bilateral involvement of the ovaries and the histopathological findings. In conclusion, we present this case to draw attention to the fact that IgG4-related disease can also be seen in the ovary.

Ovarian endometrioma infiltrating neutrophils orchestrate immunosuppressive microenvironment.

BACKGROUND: Ovarian endometrioma (EM) lesions not only have overwhelmed the amount of infiltrating immune cells but also display immunosuppressive phenotype. The close relationship between neutrophils and the pathogenesis of endometriosis has been demonstrated. The present study aims to elucidate whether or not neutrophils are involved in the regulation of immunosuppressive microenvironment in ovarian endometrioma. METHODS: Immunochemistry (IHC) and flow cytometry analysis (FACS) were conducted to measure CD66b expression in ovarian endometrioma samples from EM patients. The correlation between percentage of CD66b and PD1 + CD8+, TIM3 + CD8+, CTLA4 + CD8+, IFN-γ + CD8+ of CD45+ cells were analyzed. Neutrophil survival and PD-L1 expression were determined under the stimulations of ovarian endometrioma conditional supernatants (OECS). Finally, CD8+ T cell's proliferation and IFN-γ expression were detected under co-cultured with OECS cultured neutrophils stimulated with the α-CD3/α-CD28 antibody. RESULTS: IHC and FACS results revealed correlation between the counts of neutrophils and the severity of ovarian endometrioma. The percentage of CD66b + cells was positively correlated with PD1 + CD8+, TIM3 + CD8+ and CTLA4 + CD8+ of CD45+ cells in ovarian endometrioma. OECS promoted neutrophils' survival and enhanced PD-L1 expression. OECS cultured neutrophils inhibited proliferation and activity of autologous T cells. CONCLUSIONS: Neutrophils play a crucial role in the progression of ovarian endometrioma by orchestrated the immunosuppressive microenvironment under the PD-1/PD-L1 axis.

Evaluation of M1 and M2 macrophages in ovarian endometriomas from women affected by endometriosis at different stages of the disease.

Endometriosis is an estrogen-dependent disease defined by the presence and growth of functional endometrial-like tissue, glands and stroma, outside the uterine cavity. Macrophages are broadly classified into pro-inflammatory M1 macrophages, and M2 macrophages, which have selective anti-inflammatory and pro-fibrotic activities and are able to induce immunotolerance and angiogenesis. Based on these elements, the aim of our study was to evaluate CD14+CD68+CD197+CD80+ M1 and CD14+CD68+CD163+CD206+ M2 macrophages in tissue samples from ovarian endometriomas of women affected by endometriosis at different stages of the disease. For each patient, we collected a biological sample of the cyst (ovarian endometriomas for cases and ovarian functional cyst for controls) during laparoscopy. We found that the number of both M1 and M2 macrophages was significantly higher in endometriosis group than controls, regardless of stage (p < .0001 for each stage versus controls). Moreover, our data analysis shows a trend in progressive decrease of M1 macrophages from stage I to stage IV; on the contrary, M2 macrophages show a specular trend compared to M1 macrophages, with a progressive increase from stage I to stage IV. This may contribute to the pro-inflammatory microenvironment in the early stages of the disease, and to the pro-fibrotic activity of the advanced stages.

The Influence of Pentraxin 3 on the Ovarian Function and Its Impact on Fertility.

Follicular development is a highly coordinated process that in humans takes more than 6 months. Pituitary gonadotropins and a variety of locally produced growth factors and cytokines are involved in determining a precise sequence of changes in cell metabolism, proliferation, vascularization, and matrix remodeling in order to obtain a follicle with full ovulatory and steroidogenic capability. A low-grade inflammation can alter such processes leading to premature arrest of follicular growth and female reproductive failure. On the other hand, factors that are involved in inflammatory response as well as in innate immunity are physiologically upregulated in the follicle at the final stage of maturation and play an essential role in ovulation and fertilization. The generation of pentraxin 3 (PTX3) deficient mice provided the first evidence that this humoral pattern recognition molecule of the innate immunity has a non-redundant role in female fertility. The expression, localization, and molecular interactions of PTX3 in the periovulatory follicle have been extensively studied in the last 10 years. In this review, we summarize findings demonstrating that PTX3 is synthesized before ovulation by cells surrounding the oocyte and actively participates in the organization of the hyaluronan-rich provisional matrix required for successful fertilization. Data in humans tend to confirm these findings, indicating PTX3 as a biomarker of oocyte quality. Moreover, we discuss the emerging evidence that in humans altered PTX3 systemic levels, determined by genetic variations and/or low-grade chronic inflammation, can also impact the growth and development of the follicle and affect the incidence of ovarian disorders.

[ON THE ISSUE OF AUTOIMMUNE OVARY DAMAGE DURING PUBERTY].

The aim of the study was to ascertain the influence of AІТ on the formation of autoimmune damage to ovaries by determining the connections between the levels of AOAB, ATPO, gonadotropic and sex hormone levels, and the functional state of the ovaries and thyroid gland. 198 girls age 10-18 were studied: 166 with AIT (AIT+ Group), и 32- without AIT (the AIT- Group). A defined difference between TTH. and ATPO, was revealed, which is explained by the presence of thyroid pathology in the AIT+ Group. Prolactin levels and ovarian volume were notably higher, while Progesterone levels were lower in the AIT+ Group. No discernable differences among levels of AOAB, sex hormones, Estrogen, Testosterone or antral follicules were observed. A direct correlation was revealed between AOAB levels and the girls' age both in the AIT+ and AIT- groups. AOAB data was divided into three tertials in order to study links with various hormonal homeostasis. Analysis of data obtained showed numerous correlative links between ATPO, AOAB, gonadotropins, sex hormones, TTH and ovarian volume in all tertials of both the AIT+ and AIT- groups; correlative links were found, too, between AOAB and ATPO in the III tertial groups AIT+ and AIT-. In adolescents with AIT disbalance occurs at all levels of hormonal homeostasis as well as in ovarian structure. Such changes and the presence of ATPO and AOAB may be associated with emerging autoimmune ovary damage.

PreImplantation Factor in endometriosis: A potential role in inducing immune privilege for ectopic endometrium.

Endometriosis is a chronic inflammatory condition characterised by the growth of endometrial epithelial and stromal cells outside the uterine cavity. In addition to Sampson's theory of retrograde menstruation, endometriosis pathogenesis is facilitated by a privileged inflammatory microenvironment, with T regulatory FoxP3+ expressing T cells (Tregs) being a significant factor. PreImplantation Factor (PIF) is a peptide essential for pregnancy recognition and development. An immune modulatory function of the synthetic PIF analog (sPIF) has been successfully confirmed in multiple animal models. We report that PIF is expressed in the epithelial ectopic cells in close proximity to FoxP3+ stromal cells. We provide evidence that PIF interacts with FoxP3+ cells and modulates cell viability, dependent on cell source and presence of inflammatory mediators. Our finding represent a novel PIF-based mechanism in endometriosis that has potential for novel therapeutics.

The role of regulatory T cells in thymectomy-induced autoimmune ovarian disease.

PROBLEM: To evaluate the role of regulatory T (Treg) cells in autoimmune ovarian disease (AOD). METHOD OF STUDY: AOD model was set up by thymectomy of BALB/C mice on day 3 (d3tx). The variation of T lymphocyte subsets, especially the Treg cells were analyzed in the peripheral blood, spleen, para-aortic, and inguinal lymph nodes in d3tx mice. The effect of Treg cells on AOD was further evaluated by adoptive transfer of Treg cells into d3tx mice (d3tx+Treg). RESULTS: In d3tx mice, the ratio of Treg/CD4+ was significantly increased rapidly from 1st to 2nd week, rapidly declined in 3rd week, then decreased slowly until the 9th week. The CD3+ /T lymphocytes and the ratio of CD4+ /CD3+ were significantly decreased in the para-aortic and inguinal lymph nodes of d3tx mice, but the ratio of Treg/CD4+ and CD8+ /CD3+ were increased simultaneously. In d3tx mice with adoptive transfer of Treg cells (0.5×104 ~5×105 ), there was a significant increase in the Treg/CD4+ ratios in the spleen and peripheral blood. AOD score, especially adoptive transferred treg cells from the ovarian lymph nodes was significantly decreased. Oocytes were successfully obtained from d3tx+Treg mice, which could fertilize and develop to embryos normally. CONCLUSION: Treg cells involved in the pathogenesis of AOD. Sufficient numbers of Treg cells can modify AOD in the early phase in d3tx mice.

Characterization of endometriosis-associated immune cell infiltrates (EMaICI).

OBJECTIVE: To identify and characterize endometriosis-associated immune cell infiltrates (EMaICI). Furthermore, to define occurrence and size of EMaICI in various types of endometriosis. METHODS: Immune cells were characterized in samples of 60 premenopausal women with histological proven endometriosis. Therefore, immunohistochemical staining with monoclonal antibodies for CD3, CD4, CD8, CD45RO, CD25, CD56, CD68, and CD20 on sections of paraffin-embedded endometriotic tissue was performed. RESULTS: EMaICI were observed in all the types of endometriosis, and characterized as T lymphocytes (CD3+), helper T lymphocytes (CD4+), cytotoxic T lymphocytes (CD8+), antigen-experienced T lymphocytes"memory cells" (CD45RO+), macrophages (CD68+), and B lymphocytes (CD20+). The maximum frequency of EMaICI and their distribution per endometriotic lesion (EML) was observed in peritoneal endometriosis (pEM) and in ovarian endometriosis (Ov. EM). In myometrium from adenomyosis (M/AM), EMaICI occurrence was lower and smaller in size in comparison with EMaICI seen in other forms of endometriosis. EMaICI were negative for regulatory T cells (CD25+ high, FoxP3+) and natural killer cells (NK cells, CD56+). CONCLUSION: Numerous and brisk EMaICI comprising several types of immune cells in all endometriosis forms suggest acute immunological reactions within the microenvironment of endometriosis lesions.

Gynecological involvement in eosinophilic granulomatosis with polyangiitis.

Gynceological involvement in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides is rare. We describe a case of ANCA-associated vasculitis in an elderly woman presenting with fevers, cough and a rash. Further investigations revealed vasculitic involvement of the ovaries, fallopian tubes, uterus and omentum with an eosinophil-rich infiltrate.

Ovarian autoimmune disease: clinical concepts and animal models.

The ovary is not an immunologically privileged organ, but a breakdown in tolerogenic mechanisms for ovary-specific antigens has disastrous consequences on fertility in women, and this is replicated in murine models of autoimmune disease. Isolated ovarian autoimmune disease is rare in women, likely due to the severity of the disease and the inability to transmit genetic information conferring the ovarian disease across generations. Nonetheless, autoimmune oophoritis is often observed in association with other autoimmune diseases, particularly autoimmune adrenal disease, and takes a toll on both society and individual health. Studies in mice have revealed at least two mechanisms that protect the ovary from autoimmune attack. These mechanisms include control of autoreactive T cells by thymus-derived regulatory T cells, as well as a role for the autoimmune regulator (AIRE), a transcriptional regulator that induces expression of tissue-restricted antigens in medullary thymic epithelial cells during development of T cells. Although the latter mechanism is incompletely defined, it is well established that failure of either results in autoimmune-mediated targeting and depletion of ovarian follicles. In this review, we will address the clinical features and consequences of autoimmune-mediated ovarian infertility in women, as well as the possible mechanisms of disease as revealed by animal models.

TSLP induced by estrogen stimulates secretion of MCP-1 and IL-8 and growth of human endometrial stromal cells through JNK and NF-κB signal pathways.

It has reported that human endometrial stromal cells (ESCs) express thymic stromal lymphopoietin (TSLP), and TSLP concentrations in the serum and peritoneal fluid were higher in women with endometriosis. Endometriosis is an estrogen-dependent disease. The present study aimed to elucidate whether and how estrogen regulates the growth of ESCs through TSLP. The ESCs behaviors in vitro were verified by SRB assay and Ki67 level detection, respectively. In addition, the effects of estrogen on TSLP and TSLP on the correspondent functional molecules were investigated by ELISA and flow cytometry. Here we found that estrogen stimulated the secretion of TSLP in a dosage-dependent manner. Recombinant human TSLP stimulates the secretion of MCP-1 and IL-8, and markedly promotes the viability and proliferation relative gene Ki-67 expression of ESCs. These effects could be abolished by the inhibitor for JNK or NF-κB signal, respectively. Moreover, not only anti-TSLP neutralizing antibody, but also blocking JNK or NF-κB signal by inhibitor abrogated the stimulatory role in the production of MCP-1 and IL-8, and the growth of ESCs induced by estrogen. Our current study has demonstrated that TSLP is involved in the regulation of estrogen on the secretion of MCP-1 and IL-8, and the growth of ESCs through JNK and NF-κB signal pathways, which suggests that the abnormal high expression of TSLP induced by estrogen may play an important role in ESCs growth and finally contribute to the origin and development of endometriosis.

Elevated expression of CD147 in patients with endometriosis and its role in regulating apoptosis and migration of human endometrial cells.

OBJECTIVE: To examine the expression of CD147 in 60 human endometriosis lesions and how CD147 regulates migration and apoptosis in human uterine epithelial (HESs) cells. DESIGN: Experimental clinical study and laboratory-based investigation. SETTING: Hospital and academic research center. PATIENT(S): Sixty women with chocolate cysts and 16 control women without endometriosis. INTERVENTION(S): Human uterine epithelial cells were treated with anti-CD147 antibody. MAIN OUTCOME MEASURE(S): Real-time polymerase chain reaction for detecting CD147 expression in 60 human endometriosis lesions; migration assay and CellTiter 96 AQueous One Solution Cell Proliferation Assay (MTS) assay for cell functional investigation; Western blot for detecting protein levels; gelatin zymography for evaluating the activity of matrix metalloproteinase-2 (MMP-2) in cultured cells. RESULT(S): Expression of CD147 was significantly higher in ectopic endometrial tissues from patients with endometriosis than in normal endometrial tissues. Interference with CD147 function led to decreased migration and cell viability in HESs cells. Surprisingly, MMP-2 expression and activity were not changed after treating HESs cells with anti-CD147 antibody. Further examination revealed that immunodepletion of CD147 induced apoptosis in HESs cells, leading to the activation of caspase 3 and poly(ADP-ribose) polymerase. CONCLUSION(S): The results of the present study suggest that abnormally high expression of CD147 in ovarian endometriosis lesions with enhanced cell survival (reduced apoptosis) and migration, in an MMP-2-independent manner, may underlie the progression of endometriosis in humans.

Resveratrol suppresses inflammatory responses in endometrial stromal cells derived from endometriosis: a possible role of the sirtuin 1 pathway.

AIM: Endometriosis is a chronic inflammatory disease. Sirtuin 1 (SIRT1) plays a role in regulation of inflammation. The role of SIRT1 in endometriosis remains unknown. We here addressed the anti-inflammatory effects of SIRT1 on endometriosis. METHODS: The expression of SIRT1 in human ovarian endometriomas and eutopic endometria were examined using immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Endometriotic stromal cells (ESC) obtained from endometriomas were exposed to either resveratrol or sirtinol, an activator or inhibitor of sirtuins, respectively, and tumor necrosis factor (TNF)-α-induced interleukin (IL)-8 release from the ESC was assessed at mRNA and protein levels. RESULTS: Both immunochemistry and RT-PCR demonstrated that SIRT1 was expressed in ESC and normal endometrial stromal cells. Resveratrol suppressed TNF-α-induced IL-8 release from the ESC in a dose-dependent manner while sirtinol increased IL-8 release. CONCLUSION: These opposing effects of SIRT1-related agents suggest that IL-8 release from the ESC is modulated through the SIRT1 pathway. Resveratrol may have the potential to ameliorate local inflammation in endometriomas.

Cutting edge: Ly49C/I⁻ neonatal NK cells predispose newborns to autoimmune ovarian disease induced by maternal autoantibody.

NK cells are critical in immune responses against pathogens. However, their role in autoimmunity is still controversial. In this study, we demonstrate that neonatal NK cells render newborns more susceptible to neonatal autoimmunity induced by maternal autoantibodies (neonatal autoimmune ovarian disease); thus, neonatal but not adult NK cells are pathogenic after transfer into NK cell-deficient pups. The inhibitory receptors Ly49C/I are expressed in ∼5% of neonatal and ∼50% of adult NK cells. In this study, we show that the presence of Ly49C/I⁺ adult NK cells inhibits neonatal autoimmune ovarian disease induction. Thus, the ontogenetic regulation of Ly49C/I expression determines the propensity to autoantibody-induced autoimmunity. In summary, this study provides definitive evidence of a pathogenic role of NK cells in neonatal autoimmunity and also elucidates a novel mechanism by which neonatal NK cells render newborns more susceptible to autoantibody-induced autoimmunity.

HSP90 antibodies: a detrimental factor responsible for ovarian dysfunction.

PROBLEM: Earlier studies from our group have established that about 47% cases of autoimmune ovarian failure are due to presence of autoantibodies to Heat Shock Protein 90 (HSP90). However, there are no reports correlating pathological effects of HSP90 autoantibodies leading to ovarian failure. METHOD OF STUDY: Antibodies to HSP90 in female mouse model were generated by active immunization with an immunodominant peptide of HSP90, followed by detailed analysis of several reproductive parameters. RESULT: Estrous cyclicity remains unchanged; however, there was a significant drop in the fertility index due to an increase in pre- and post-implantation loss, associated with an increased incidence of degenerated eggs and embryos. The ovaries showed an increase in the number of empty and degenerated follicles and extensive granulosa cell deaths, which was reflected by the decrease in the levels of Nobox and Gja1 gene expression. CONCLUSION: This study underlines a critical role played by HSP90 in ovarian folliculogenesis and highlights the implications of the presence of anti-HSP90 antibodies in infertile women.

The adjuvant use of N-palmitoylethanolamine and transpolydatin in the treatment of endometriotic pain.

OBJECTIVE: To test the adjuvant use of the combination of N-palmitoylethanolamine and transpolydatin in the medical treatment of endometriotic pain. STUDY DESIGN: We enrolled 47 patients admitted to the Outpatient Endometriosis Care Unit of Ferrara University from January 2011 to December 2011. They were divided into two groups according to the endometriosis site (group A: recto-vaginal septum; group B: ovary). One tablet, containing 400 mg of micronized N-palmitoylethanolamine plus 40 mg transpolydatin, was administered twice daily on a full stomach for 90 days. Each patient was requested to grade the severity of dysmenorrhea, chronic pelvic pain, dyspareunia and dyschezia using a 0-10 cm visual analogic scale prior to beginning treatment (T0), after 30 days (T1), 60 days (T2) and 90 days (T3). The continuous and categorical variables were compared, respectively, using Student's t-test and the chi-square test. Analysis of variance for repeated measures was used to verify the reduction of endometriotic pain. RESULTS: The intensity of endometriotic pain decreased significantly for both groups (p<0.0001). The efficacy of drug treatment was significant after 30 days. Pain intensity decreased equally in the two groups except for dysmenorrhea, which was reduced more rapidly in group B. CONCLUSIONS: The combination of N-palmitoylethanolamine and transpolydatin reduced pain related to endometriosis irrespective of lesion site. It had a marked effect on chronic pelvic pain determined by deep endometriosis and on dysmenorrhea correlated to ovarian endometriosis.

Pelvic pain in women with ovarian endometrioma is mostly associated with coexisting peritoneal lesions.

STUDY QUESTION: Is the occurrence of pelvic pain in women with ovarian endometrioma associated with coexisting peritoneal lesions (PLs)? SUMMARY ANSWER: Pelvic pain in women with ovarian endometrioma is usually associated with coexisting PLs. An increased tissue inflammatory reaction with elevated prostaglandin (PG) production may be responsible for the generation of pain. WHAT IS KNOWN ALREADY: Severe pelvic pain in women with ovarian endometrioma is reported to be associated with deeply infiltrating endometriosis. However, information on pelvic pain in women with ovarian endometriosis with and without coexistent peritoneal superficial lesions is limited. STUDY DESIGN, SIZE AND DURATION: Retrospective clinical study with case-controlled biological research using prospectively collected tissue samples derived from women with and without endometriosis and their retrospective evaluation. PARTICIPANTS/MATERIALS, SETTING, METHODS: We performed a retrospective cohort study conducted in 2988 cases who had laparoscopic surgery for indications of ectopic pregnancy, tubal infertility and other benign gynecologic diseases. We analyzed the occurrence of pelvic pain in the cases with ovarian endometrioma according to the distribution of coexisting PLs and pattern of intrapelvic adhesions. Inflammatory reaction of eutopic and ectopic endometria was measured by immunoreaction to macrophage marker, CD68. The tissue expression of cyclooxygenase (COX) 2 was examined by immunohistochemistry and tissue concentrations of PG F2α were measured by ELISA. MAIN RESULTS AND THE ROLE OF CHANCE: Among the 2988 surgical cases, 350 (11.7%) were found to have ovarian endometrioma at laparoscopy. Coexisting PLs were present in 269 of these women and in this group 85.4% of cases experienced pelvic pain and 14.6% had no pain. In contrast, among the 81 women with ovarian endometrioma only, 38.3% cases experienced pelvic pain and 61.7% cases had no pain and the difference between the groups was statistically significant (P < 0.01). The infiltration of CD68-immunoreactive macrophages was significantly higher in the eutopic and ectopic endometria of women with peritoneal endometriosis than in ovarian endometrioma. The tissue expression of COX2 and levels of PGF2α were significantly higher in both the eutopic and ectopic endometria derived from women with peritoneal endometriosis than in similar tissues derived from women with ovarian endometrioma. LIMITATIONS, REASONS FOR CAUTIONS: Lack of evaluation in the detection of general or disseminated deeply infiltrating endometriosis in the pelvic cavity could be a bias or limitation in this study. Further multicenter prospective studies are needed to strengthen our current findings. WIDER IMPLICATIONS OF THE FINDINGS: Our findings may provide some new insights to understand the physiopathology of pelvic pain in women with ovarian cystic endometriosis and may hint at proper surgical manipulation to prevent the recurrence of pelvic pain in these women. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Sports, Culture, Science and Technology of Japan. There is no conflict of interest related to this study. TRIAL REGISTRATION NUMBER: Not applicable.

The efficacy of three commercial Mycoplasma gallisepticum vaccines in laying hens.

The efficacy of three commercial Mycoplasma gallisepticum (MG) immunizing agents-a bacterin, a recombinant fowlpox-MG vaccine, and a live F-strain vaccine-was compared in specific-pathogen-free hens in egg production. Three groups of 25 chickens were vaccinated with one of the vaccines at 10 wk of age and 25 birds were not vaccinated. At 25 wk of age (and approximately 50% egg production), 20 birds from each of the three vaccinated groups and 15 nonvaccinated controls were challenged with virulent R-strain via aerosol; the birds were necropsied and evaluated at 10 days post-challenge. The MG bacterin and live F-strain vaccinations were both protective and resulted in significant differences in air sac lesions, tracheal lesions, and ovarian regression compared to the nonvaccinated controls and the recombinant fowlpox-MG vaccine (P < or = 0.05). The evaluation of ovarian regression is a useful method of testing the efficacy of MG vaccines in laying hens.