An institution-wide faculty mentoring program at an academic health center with 6-year prospective outcome data.

BACKGROUND: There is discontent and turnover among faculty at US academic health centers because of the challenges in balancing clinical, research, teaching, and work-life responsibilities in the current healthcare environment. One potential strategy to improve faculty satisfaction and limit turnover is through faculty mentoring programs. METHODS: A Mentor Leadership Council was formed to design and implement an institution-wide faculty mentoring program across all colleges at an academic health center. The authors conducted an experimental study of the impact of the mentoring program using pre-intervention (2011) and 6-year (2017) post-intervention faculty surveys that measured the long-term effectiveness of the program. RESULTS: The percent of faculty who responded to the surveys was 45.9% (656/1428) in 2011 and 40.2% (706/1756) in 2017. For faculty below the rank of full professor, percent of faculty with a mentor (45.3% vs. 67.1%, P < 0.001), familiarity with promotion criteria (81.7% vs. 90.0%, P = 0.001), and satisfaction with department's support of career (75.6% vs. 84.7%, P = 0.002) improved. The percent of full professors serving as mentors also increased from 50.3% in 2011 to 68.0% in 2017 (P = 0.002). However, the percent of non-retiring faculty considering leaving the institution over the next 2 years increased from 18.8% in 2011 to 24.3% in 2017 (P = 0.02). CONCLUSIONS: Implementation of an institution-wide faculty mentoring program significantly improved metrics of career development and faculty satisfaction but was not associated with a reduction in the percent of faculty considering leaving the institution. This suggests the need for additional efforts to identify and limit factors driving faculty turnover.

Immunogenicity of a chimeric Plasmodium falciparum merozoite surface protein vaccine in Aotus monkeys.

BACKGROUND: The production of properly folded, recombinant sub-unit Plasmodium falciparum malaria vaccine candidates in sufficient quantities is often a challenge. Success in vaccine immunogenicity studies in small animal models does not always predict immunogenicity in non-human primates and/or human subjects. The aim of this study was to assess the immunogenicity of a chimeric blood-stage malaria vaccine in Aotus monkeys. This vaccine candidate includes the neutralizing B cell epitopes of P. falciparum merozoite surface protein 1 (rPfMSP119) genetically linked to a highly immunogenic, well-conserved P. falciparum merozoite surface protein 8 (rPfMSP8 (ΔAsn/Asp)) partner. METHODS: Aotus nancymaae monkeys were immunized with purified rPfMSP1/8 or rPfMSP8 (ΔAsn/Asp) formulated with Montanide ISA 720 as adjuvant, or with adjuvant alone. Antibody responses to MSP119 and MSP8 domains were measured by ELISA following primary, secondary and tertiary immunizations. The functionality of vaccine-induced antibodies was assessed in a standard P. falciparum blood-stage in vitro growth inhibition assay. Non-parametric tests with corrections for multiple comparisons when appropriate were used to determine the significance of differences in antigen-specific IgG titres and in parasite growth inhibition. RESULTS: The chimeric rPfMSP1/8 vaccine was shown to be well tolerated and highly immunogenic with boost-able antibody responses elicited to both PfMSP8 and PfMSP119 domains. Elicited antibodies were highly cross-reactive between FVO and 3D7 alleles of PfMSP119 and potently inhibited the in vitro growth of P. falciparum blood-stage parasites. CONCLUSIONS: Similar to previous results with inbred and outbred mice and with rabbits, the PfMSP1/8 vaccine was shown to be highly effective in eliciting P. falciparum growth inhibitory antibodies upon immunization of non-human primates. The data support the further assessment of PfMSP1/8 as a component of a multivalent vaccine for use in human subjects. As important, the data indicate that rPfMSP8 (ΔAsn/Asp) can be used as a malaria specific carrier protein to: (1) drive production of antibody responses to neutralizing B cell epitopes of heterologous vaccine candidates and (2) facilitate production of properly folded, recombinant P. falciparum subunit vaccines in high yield.

Protective efficacy of a Plasmodium vivax circumsporozoite protein-based vaccine in Aotus nancymaae is associated with antibodies to the repeat region.

We have previously reported that Vivax Malaria Protein 001 (VMP001), a vaccine candidate based on the circumsporozoite protein of Plasmodium vivax, is immunogenic in mice and rhesus monkeys in the presence of various adjuvants. In the present study, we evaluated the immunogenicity and efficacy of VMP001 formulated with a TLR9 agonist in a water-in-oil emulsion. Following immunization, the vaccine efficacy was assessed by challenging Aotus nancymaae monkeys with P. vivax sporozoites. Monkeys from both the low- and high-dose vaccine groups generated strong humoral immune responses to the vaccine (peak median titers of 291,622), and its subunits (peak median titers to the N-term, central repeat and C-term regions of 22,188; 66,120 and 179,947, respectively). 66.7% of vaccinated monkeys demonstrated sterile protection following challenge. Protection was associated with antibodies directed against the central repeat region. The protected monkeys had a median anti-repeat titer of 97,841 compared to 14,822 in the non-protected monkeys. This is the first report demonstrating P. vivax CSP vaccine-induced protection of Aotus monkeys challenged with P. vivax sporozoites.

Schistosoma mansoni infection impairs antimalaria treatment and immune responses of rhesus macaques infected with mosquito-borne Plasmodium coatneyi.

Malaria and schistosomiasis are the world's two most important parasitic infections in terms of distribution, morbidity, and mortality. In areas where Plasmodium and Schistosoma species are both endemic, coinfections are commonplace. Mouse models demonstrate that schistosomiasis worsens a malaria infection; however, just as mice and humans differ greatly, the murine-infecting Plasmodium species differ as much from those that infect humans. Research into human coinfections (Schistosoma haematobium-Plasmodium falciparum versus Schistosoma mansoni-P. falciparum) has produced conflicting results. The rhesus macaque model provides a helpful tool for understanding the role of S. mansoni on malaria parasitemia and antimalarial immune responses using Plasmodium coatneyi, a malaria species that closely resembles P. falciparum infection in humans. Eight rhesus macaques were exposed to S. mansoni cercariae. Eight weeks later, these animals plus 8 additional macaques were exposed to malaria either through bites of infected mosquitos or intravenous inoculation. When malaria infection was initiated from mosquito bites, coinfected animals displayed increased malaria parasitemia, decreased hematocrit levels, and suppressed malaria-specific antibody responses compared to those of malaria infection alone. However, macaques infected by intravenous inoculation with erythrocytic-stage parasites did not display these same differences in parasitemia, hematocrit, or antibody responses between the two groups. Use of the macaque model provides information that begins to unravel differences in pathological and immunological outcomes observed between humans with P. falciparum that are coinfected with S. mansoni or S. haematobium. Our results suggest that migration of malaria parasites through livers harboring schistosome eggs may alter host immune responses and infection outcomes.

Mosquito infection studies with Aotus monkeys and humans infected with the Chesson strain of Plasmodiun vivax.

Oocyst counts were compared between mosquitoes that fed on humans versus mosquitoes that fed on Aotus monkeys, both of which were infected with the Chesson strain of Plasmodium vivax. Oocyst counts obtained from mosquitoes fed on humans were almost 10-fold higher in number. Mosquitoes were more likely to be infected and with a higher rate of infection when they fed on monkeys before the peak in the asexual parasite count. Mosquitoes that fed on humans were more likely to be more heavily infected when fed after the peak in the asexual count. Of several species of owl monkeys, Aotus vociferans was infected at a higher frequency. On the basis of oocyst counts, Anopheles dirus were the most susceptible and An. maculatus were the least susceptible of the mosquito species tested.

Evidence for an increased risk of transmission of simian immunodeficiency virus and malaria in a rhesus macaque coinfection model.

In sub-Saharan Africa, HIV-1 infection frequently occurs in the context of other coinfecting pathogens, most importantly, Mycobacterium tuberculosis and malaria parasites. The consequences are often devastating, resulting in enhanced morbidity and mortality. Due to the large number of confounding factors influencing pathogenesis in coinfected people, we sought to develop a nonhuman primate model of simian immunodeficiency virus (SIV)-malaria coinfection. In sub-Saharan Africa, Plasmodium falciparum is the most common malaria parasite and is responsible for most malaria-induced deaths. The simian malaria parasite Plasmodium fragile can induce clinical symptoms, including cerebral malaria in rhesus macaques, that resemble those of P. falciparum infection in humans. Thus, based on the well-characterized rhesus macaque model of SIV infection, this study reports the development of a novel rhesus macaque SIV-P. fragile coinfection model to study human HIV-P. falciparum coinfection. Using this model, we show that coinfection is associated with an increased, although transient, risk of both HIV and malaria transmission. Specifically, SIV-P. fragile coinfected macaques experienced an increase in SIV viremia that was temporarily associated with an increase in potential SIV target cells and systemic immune activation during acute parasitemia. Conversely, primary parasitemia in SIV-P. fragile coinfected animals resulted in higher gametocytemia that subsequently translated into higher oocyst development in mosquitoes. To our knowledge, this is the first animal model able to recapitulate the increased transmission risk of both HIV and malaria in coinfected humans. Therefore, this model could serve as an essential tool to elucidate distinct immunological, virological, and/or parasitological parameters underlying disease exacerbation in HIV-malaria coinfected people.

Detection of Plasmodium falciparum, P. vivax, P. ovale, and P. malariae merozoite surface protein 1-p19 antibodies in human malaria patients and experimentally infected nonhuman primates.

Approximately 3.2 billion people live in areas where malaria is endemic, and WHO estimates that 350 to 500 million malaria cases occur each year worldwide. This high prevalence, and the high frequency of international travel, creates significant risk for the exportation of malaria to countries where malaria is not endemic and for the introduction of malaria organisms into the blood supply. Since all four human infectious Plasmodium species have been transmitted by blood transfusion, we sought to develop an enzyme-linked immunosorbent assay (ELISA) capable of detecting antibodies elicited by infection with any of these species. The merozoite surface protein 1 (MSP1), a P. falciparum and P. vivax vaccine candidate with a well-characterized immune response, was selected for use in the assay. The MSP1 genes from P. ovale and P. malariae were cloned and sequenced (L. Birkenmeyer, A. S. Muerhoff, G. Dawson, and S. M. Desai, Am. J. Trop. Med. Hyg. 82:996-1003, 2010), and the carboxyl-terminal p19 regions of all four species were expressed in Escherichia coli. Performance results from individual p19 ELISAs were compared to those of a commercial test (Lab 21 Healthcare Malaria enzyme immunoassay [EIA]). The commercial ELISA detected all malaria patients with P. falciparum or P. vivax infections, as did the corresponding species-specific p19 ELISAs. However, the commercial ELISA detected antibodies in 0/2 and 5/8 individuals with P. malariae and P. ovale infections, respectively, while the p19 assays detected 100% of individuals with confirmed P. malariae or P. ovale infections. In experimentally infected nonhuman primates, the use of MSP1-p19 antigens from all four species resulted in the detection of antibodies within 2 to 10 weeks postinfection. Use of MSP1-p19 antigens from all four Plasmodium species in a single immunoassay would provide significantly improved efficacy compared to existing tests.

High antibody titer against apical membrane antigen-1 is required to protect against malaria in the Aotus model.

A Plasmodium falciparum 3D7 strain Apical Membrane Antigen-1 (AMA1) vaccine, formulated with AS02(A) adjuvant, slowed parasite growth in a recent Phase 1/2a trial, however sterile protection was not observed. We tested this AS02(A), and a Montanide ISA720 (ISA) formulation of 3D7 AMA1 in Aotus monkeys. The 3D7 parasite does not invade Aotus erythrocytes, hence two heterologous strains, FCH/4 and FVO, were used for challenge, FCH/4 AMA1 being more homologous to 3D7 than FVO AMA1. Following three vaccinations, the monkeys were challenged with 50,000 FCH/4 or 10,000 FVO parasites. Three of the six animals in the AMA+ISA group were protected against FCH/4 challenge. One monkey did not become parasitemic, another showed only a short period of low level parasitemia that self-cured, and a third animal showed a delay before exhibiting its parasitemic phase. This is the first protection shown in primates with a recombinant P. falciparum AMA1 without formulation in Freund's complete adjuvant. No animals in the AMA+AS02(A) group were protected, but this group exhibited a trend towards reduced growth rate. A second group of monkeys vaccinated with AMA+ISA vaccine was not protected against FVO challenge, suggesting strain-specificity of AMA1-based protection. Protection against FCH/4 strain correlated with the quantity of induced antibodies, as the protected animals were the only ones to have in vitro parasite growth inhibitory activity of >70% at 1:10 serum dilution; immuno-fluorescence titers >8,000; ELISA titers against full-length AMA1 >300,000 and ELISA titer against AMA1 domains1+2 >100,000. A negative correlation between log ELISA titer and day 11 cumulative parasitemia (Spearman rank r = -0.780, p value = 0.0001), further confirmed the relationship between antibody titer and protection. High titers of cross-strain inhibitory antibodies against AMA1 are therefore critical to confer solid protection, and the Aotus model can be used to down-select future AMA1 formulations, prior to advanced human trials.

Infection of mosquitoes with Plasmodium falciparum by feeding on humans and on Aotus monkeys.

Of 1,004 positive lots of mosquitoes fed on 229 humans infected with Plasmodium falciparum, 46.2% had 1-10 oocysts/(+)gut, 21.2% had 10-30 oocysts/(+)gut, 22.2% had 30-100 oocysts/(+)gut, and 10.4% had > 100 oocysts/(+) gut. The highest levels of infection occurred between 6 and 15 days after the peak in the asexual parasite count. Of 2,281 lots of Anopheles freeborni mosquitoes fed on splenectomized Aotus monkeys infected with the Santa Lucia strain of P. falciparum, 1,191 were infected (52.2%). The highest intensity infections ranged from 2.78 oocysts per positive gut in mosquitoes fed on Aotus vociferans to 6.08 oocysts per positive gut for those fed on A. lemurinus griseimembra to 10.4 oocysts per positive gut for those fed on A. nancymaae. The pattern of infection for mosquitoes fed on splenectomized Aotus monkeys was similar to that obtained by feeding on humans, but the intensity, based on oocyst/(+)gut, was much lower.

Plasmodium fieldi: observations on the Hackeri and ABI strains in Macaca mulatta monkeys and mosquitoes.

Macaca mulatta monkeys infected with the Hackeri strain of Plasmodium fieldi had maximum parasite counts ranging from 1,300 to 301,320/microL. In 43 intact animals infected with the ABI strain, the maximum parasite counts ranged from 672 to 57,189/microL (median = 15,100/microL); in 46 splenectomized monkeys, the maximum parasite count ranged from 660 to 350,000/microL (median = 52,245/microL). Transmission through Anopheles dirus mosquitoes was obtained on 11 occasions with pre-patent periods of 9-14 days. Relapses occurred between two and eight times during a 1-year period. P. fieldi has potential for testing prophylactic and radical curative drugs.

The Santa Lucia strain of Plasmodium falciparum in Aotus monkeys.

The Santa Lucia strain of Plasmodium falciparum was studied in 150 Aotus lemurinus griseimembra, 30 A. azarae boliviensis, 103 A. nancymaae, and 121 A. vociferans monkeys. All four of these splenectomized hosts supported the production of gametocytes infective to Anopheles freeborni mosquitoes. Transmission through sporozoites from An. freeborni, An. stephensi, An. maculatus, and An. albimanus mosquitoes was successful to all four species of Aotus on a total of 100 occasions with a median pre-patent period of 21 days. For the production of infective mosquitoes for vaccine challenge studies, A. l. griseimembra and A. vociferans were the most predictable hosts.

Conformational stability from rare gas solutions, r0 structural parameters, barriers to internal rotation, and ab initio calculations for vinyl silyl fluoride.

The Raman (3300-10 cm(-1)) and infrared (3300-40 cm(-1)) spectra of gaseous and solid vinyl silyl fluoride, CH(2)=CHSiH(2)F, have been recorded. Raman spectrum of the liquid has also been recorded and depolarization values obtained. Variable-temperature studies of the infrared spectra of the sample dissolved in liquid krypton (-110 to -150 degrees C) and liquid xenon (-60 to -100 degrees C) have been carried out. From these studies, the enthalpy difference has been determined to be 76 +/- 7 cm(-1) (0.91 +/- 0.08 kJ/mol) from the krypton solutions and 69 +/- 7 cm(-1) (0.82 +/- 0.08 kJ/mol) from the xenon solutions, with the gauche conformer the more stable form. From the far-infrared spectrum of the gas, the asymmetric torsional fundamentals for the cis and gauche conformers have been observed at 102.34 and 86.56 cm(-1), respectively, with each having several "hot bands" falling to lower frequencies. From these frequencies along with the experimentally determined conformational enthalpy difference, as well as the gauche skeletal dihedral angle, the potential function governing the conformational interchange has been determined with the following Fourier cosine potential coefficients: V(1) = -80 +/- 11, V(2) = -42 +/- 15, V(3) = 622 +/- 5, V(4) = 34 +/- 5, and V(6) = -31 +/- 2 cm(-1). The gauche-to-cis and gauche-to-gauche barriers are 664 cm(-1) (7.94 kJ/mol) and 608 cm(-1) (7.27 kJ/mol), respectively. Complete vibrational assignments are provided for both conformers. In addition, equilibrium geometries and electronic energies have been determined for both rotamers from ab initio calculations using restricted Hartree-Fock and Møller-Plesset perturbation method to the second order (MP2), as well as density functional theory by the B3LYP methods, employing a number of basis sets up to 6-311+G(2df,2pd). All levels of calculation predict the gauche conformer to be the more stable form. By systematically adjusting the ab initio predicted structural values to fit the previously reported microwave rotational constants, adjusted r(0) parameters have been obtained for both conformers. These values are compared to those for the corresponding chloride and methyl compounds. The spectroscopic and theoretical results are discussed and compared to the corresponding quantities for some similar molecules.

Studies on the Salvador I strain of Plasmodium vivax in non-human primates and anopheline mosquitoes.

A review is presented on studies conducted in New World monkeys and chimpanzees with the Salvador I strain of Plasmodium vivax. This isolate has been adapted to Aotus and Saimiri (squirrel) monkeys and developed as a model for the testing of antimalarial vaccines. After the injection of 10,000 sporozoites, the median prepatent period in S. boliviensis monkeys was 21.5 days. In 103 sporozoite-induced infections in splenectomized monkeys, the median maximum parasite count ranged from 2,139 to 202,368/microL, with a median maximum parasite count of 48,174/microL. Median maximum parasite counts in Aotus lemurinus griseimembra, A. nancymaae, A. azarae boliviensis, and A. vociferans monkeys were 19,902, 18,390, 21,420, and 18,210/microL, respectively and ranged from 124 to 156,000/microL. Mosquito infections were readily obtained in different species of Anopheles mosquitoes. The S. boliviensis monkey and Salvador I strain seems suitable for the testing of sporozoite and liver stage vaccines but not for blood-stage vaccines against P. vivax unless adapted further in spleen-intact Saimiri boliviensis monkeys.

The Chesson strain of plasmodium vivax in humans and different species of Aotus monkeys.

Comparison was made between the parasitemia of Chesson strain Plasmodium vivax in humans and in splenectomized Aotus lemurinus griseimembra, A. nancymaae, A. vociferans, and A. azarae boliviensis monkeys. In the monkeys, 56.3% of the animals had maximum counts > 25,000/muL and in humans 59.6% were above this peak parasitemia. In humans, it took an average of 9.3 days to reach the maximum parasite count. In monkeys with no previous infections, it took an average of 18.9 days to reach the maximum parasite count; for those with previous infections, it took an average of 15 days. Human and nonhuman primate data on this parasite suggest that splenectomized Aotus monkeys, particularly A. lemurinus griseimembra, and to a somewhat lesser extent A. vociferans, can mimic the course of Chesson malaria in humans regarding parasitemia and mosquito infection.

Plasmodium inui shortii: studies in old world and new world monkeys.

Plasmodium inui shortti was studied in monkeys (66 Macaca mulatta, 2 M. fascicularis, 12 Saimiri boliviensis, 4 Aotus lemurinus griseimembra, and 1 A. nancymaae). Prepatent periods for 30 sporozoite transmissions by Anopheles stephensi, An. dirus, and An. maculatus mosquitoes ranged from 10 to 48 days with a median of 15.5 days. In rhesus monkeys, mean maximum parasite counts for intact animals were 181,970/muL; for splenectomized animals, the mean maximum parasite count was 1,167,890/muL.

Transmission of different strains of Plasmodium cynomolgi to Aotus nancymaae monkeys and relapse.

Forty-four splenectomized Aotus nancymaae monkeys were infected with 6 different strains of Plasmodium cynomolgi, 11 via trophozoites and 33 via sporozoites. Sporozoites from Anopheles dirus, Anopheles freeborni, Anopheles gambiae, Anopheles maculatus, and Anopheles stephensi resulted in prepatent periods ranging from 9 to 39 days (median of 15 days). Importantly, relapse was demonstrated in 5 of 5 sporozoite-induced infections with the Rossan strain following treatment with chloroquine.

Protection induced by Plasmodium falciparum MSP1(42) is strain-specific, antigen and adjuvant dependent, and correlates with antibody responses.

Vaccination with Plasmodium falciparum MSP1(42)/complete Freund's adjuvant (FA) followed by MSP1(42)/incomplete FA is the only known regimen that protects Aotus nancymaae monkeys against infection by erythrocytic stage malaria parasites. The role of adjuvant is not defined; however complete FA cannot be used in humans. In rodent models, immunity is strain-specific. We vaccinated Aotus monkeys with the FVO or 3D7 alleles of MSP1(42) expressed in Escherichia coli or with the FVO allele expressed in baculovirus (bv) combined with complete and incomplete FA, Montanide ISA-720 (ISA-720) or AS02A. Challenge with FVO strain P. falciparum showed that suppression of cumulative day 11 parasitemia was strain-specific and could be induced by E. coli expressed MSP1(42) in combination with FA or ISA-720 but not with AS02A. The coli42-FVO antigen induced a stronger protective effect than the bv42-FVO antigen, and FA induced a stronger protective effect than ISA-720. ELISA antibody (Ab) responses at day of challenge (DOC) were strain-specific and correlated inversely with c-day 11 parasitemia (r = -0.843). ELISA Ab levels at DOC meeting a titer of at least 115,000 ELISA Ab units identified the vaccinees not requiring treatment (noTx) with a true positive rate of 83.3% and false positive rate of 14.3 %. Correlation between functional growth inhibitory Ab levels (GIA) and cumulative day 11 parasitemia was weaker (r = -0.511), and was not as predictive for a response of noTx. The lowest false positive rate for GIA was 30% when requiring a true positive rate of 83.3%. These inhibition results along with those showing that antigen/FA combinations induced a stronger protective immunity than antigen/ISA-720 or antigen/AS02 combinations are consistent with protection as ascribed to MSP1-specific cytophilic antibodies. Development of an effective MSP1(42) vaccine against erythrocytic stage P. falciparum infection will depend not only on antigen quality, but also upon the selection of an optimal adjuvant component.

Observations on the sporozoite transmission of Plasmodium vivax to monkeys.

Saimiri boliviensis monkeys were infected via sporozoites with the Salvador I strain of Plasmodium vivax that had been stored frozen for periods ranging from 12 to 5,312 days. Prepatent periods ranged from 16 to 53 days.

Adaptation of a multi-drug resistant strain of Plasmodium falciparum from Peru to Aotus lemurinus griseimembra, A. nancymaae, and A. vociferans monkeys.

A strain of Plasmodium falciparum from Peru was adapted to splenectomized Aotus nancymaae and Aotus vociferans monkeys. The Peru 134/CDC strain of P. falciparum was shown to be resistant to treatment with chloroquine in monkeys and partially resistant to mefloquine and malarone. Genetic mutations in crt, dhfr, dhps, and cytochrome b genes conferring drug resistance were also determined for this Peruvian strain of P. falciparum.