Jennifer M. Smith

Estradiol selectively regulates innate immune function by polarized human uterine epithelial cells in culture

The goal of this study was to examine the role of E2 in regulating innate immune protection by human uterine epithelial cells (UECs). Recognizing that UECs produce cytokines and chemokines to recruit and activate immune cells as well as viral and bacterial antimicrobials, we sought to examine the effect of E2 on constitutive and Toll-like receptor (TLR) agonist (lipopolysaccharide (LPS) and poly (I:C))-induced immune responses. The secretion by polarized UECs in culture of interleukin (IL)-6, macrophage inhibitory factor (MIF), and secretory leukocyte protease inhibitor (SLPI) was examined as well as the mRNA expression of human β-defensin-2 (HBD2), tumor necrosis factor (TNF)-α, IL-8, and nuclear factor (NF)-kB. When incubated with E2 for 24–48 h, we found that E2 stimulated UEC secretion of SLPI (fourfold) and mRNA expression of HBD2 (fivefold). Moreover, when antibacterial activity in UEC secretions was measured using Staphylococcus aureus, E2 increased the secretion of soluble factor(s) with antibacterial activity. In contrast, E2 had no effect on constitutive secretion of proinflammatory cytokines and chemokines by UECs but completely inhibited LPS- and poly (I:C)-induced secretion of MIF, IL-6, and IL-8. Estradiol also reversed the stimulatory effects of IL-1β on mRNA expression of TNF-α, IL-8, and NF-kB by 85, 95, and 70%, respectively. As SLPI is known to inhibit NF-kB expression, these findings suggest that E2 inhibition of proinflammatory cytokines may be mediated through SLPI regulation of NF-kB. Overall, these findings indicate that the production of cytokines, chemokines, and antimicrobials by UECs are differentially regulated by E2. Further, it suggests that with E2 regulation, epithelial cells that line the uterine cavity have evolved immunologically to be sensitive to viral and bacterial infections as well as the constraints of procreation.

Gender Specific Differences in the Immune Response to Infection

There are many instances where males and females differ in the susceptibility to infections. The reason for these differences in susceptibility is multifactorial. The primary cause is thought to be due to differences induced by sex hormones and their effects on gene expression as well as the immune system, but may also be due to innate physiological differences between males and females. This review summarizes gender specific differences seen in infections caused by bacteria, fungi, parasites and viruses. Ultimately, gender specific differences appear to be dependent on the microbe causing the infection, as not every infection with a specific microbial type results in increased susceptibility of one gender over the other. This suggests that there is an interaction between gender specific immune differences and the specific immune response to individual microbes.

Epithelial cell secretions from the human female reproductive tract inhibit sexually transmitted pathogens and Candida albicans but not Lactobacillus

Female reproductive tract (FRT) epithelial cells protect against potential pathogens and sexually transmitted infections. The purpose of this study was to determine if epithelial cells from the upper FRT secrete antimicrobials that inhibit reproductive tract pathogens that threaten womens health. Apical secretions from primary cultures of Fallopian tube, uterine, cervical, and ectocervical epithelial cells were incubated with Neisseria gonorrhoeae, Candida albicans (yeast and hyphal forms), human immunodeficiency virus 1 (HIV-1), and Lactobacillus crispatus before being tested for their ability to grow and/or infect target cells. Epithelial cell secretions from the upper FRT inhibit N. gonorrhoeae and both forms of Candida, as well as reduce HIV-1 (R5) infection of target cells. In contrast, none had an inhibitory effect on L. crispatus. An analysis of cytokines and chemokines in uterine secretions revealed several molecules that could account for pathogen inhibition. These findings provide definitive evidence for the critical role of epithelial cells in protecting the FRT from infections, without comprising the beneficial presence of L. crispatus, which is part of the normal vaginal microflora of humans.

The role of host gender in the pathogenesis of Cryptococcus neoformans infections.

Cryptococcus neoformans (Cn) is a pathogenic yeast and the cause of cryptococcal meningitis. Prevalence of disease between males and females is skewed, with males having an increased incidence of disease. Based on the reported gender susceptibility differences to Cn in the literature, we used clinical isolates from Botswanan HIV-infected patients to test the hypothesis that different gender environments exerted different selective pressures on Cn. When we examined this data set, we found that men had significantly higher risk of death despite having significantly higher CD4+ T lymphocyte counts upon admittance to the hospital. These observations suggested that Cn strains are uniquely adapted to different host gender environments and that the male immune response may be less efficient in controlling Cn infection. To discriminate between these possibilities, we tested whether there were phenotypic differences between strains isolated from males and females and whether there was an interaction between Cn and the host immune response. Virulence phenotypes showed that Cn isolates from females had longer doubling times and released more capsular glucoronoxylomannan (GXM). The presence of testosterone but not 17-β estradiol was associated with higher levels of GXM release for a laboratory strain and 28 clinical isolates. We also measured phagocytic efficiency, survival of Cn, and amount of killing of human macrophages by Cn after incubation with four isolates. While macrophages from females phagocytosed more Cn than macrophages from males, male macrophages had a higher fungal burden and showed increased killing by Cn. These data are consistent with the hypothesis that differential interaction between Cn and macrophages within different gender environments contribute to the increased prevalence of cryptococcosis in males. This could be related to differential expression of cryptococcal virulence genes and capsule metabolism, changes in Cn phagocytosis and increased death of Cn-infected macrophages.

Pathogen Recognition in the Human Female Reproductive Tract: Expression of Intracellular Cytosolic Sensors NOD1, NOD2, RIG-1, and MDA5 and response to HIV-1 and Neisseria gonorrhea

Expression patterns and regulation of cytosolic pattern recognition receptors (PRR) NOD‐1, NOD‐2, RIG‐1, and MDA5 have not been elucidated in the human female reproductive tract (FRT).

Effects of menstrual cycle status and gender on human neutrophil phenotype.

The effects of gender and fluctuating ovarian hormones on neutrophil phenotype have yet to be characterized.

Bringing the Excitement and Motivation of Research to Students; Using Inquiry and Research-Based Learning in a Year-Long Biochemistry Laboratory: Part II--Research-Based Laboratory--A Semester-Long Research Approach Using Malate Dehydrogenase as a Research Model.

Research‐based learning in a teaching environment is an effective way to help bring the excitement and experience of independent bench research to a large number of students. The program described here is the second of a two‐semester biochemistry laboratory series. Here, students are empowered to design, execute and analyze their own experiments for the entire semester. This style of laboratory replaces a variety of shorter labs in favor of an in depth research‐based learning experience. The concept is to allow students to function in independent research groups. The research projects are focused on a series of wild‐type and mutant clones of malate dehydrogenase. A common research theme for the laboratory helps instructors administer the course and is key to delivering a research opportunity to a large number of students. The outcome of this research‐based learning laboratory results in students who are much more confident and skilled in critical areas in biochemistry and molecular biology. Students with research experience have significantly higher confidence and motivation than those students without a previous research experience. We have also found that all students performed better in advanced courses and in the workplace.

Differential regulation of neutrophil chemotaxis to IL-8 and fMLP by GM-CSF: lack of direct effect of oestradiol

Neutrophils are a normal constituent of the female reproductive tract and their numbers increase in the late secretory phase of the menstrual cycle prior to menses. Several cytokines are produced in female reproductive tract tissue. In particular granulocyte–macrophage colony‐stimulating factor (GM‐CSF), a potent activator of neutrophils, is secreted in high concentrations by female reproductive tract epithelia. We previously observed that GM‐CSF synergizes strongly with interleukin‐8 (IL‐8) in enhancing chemotaxis of neutrophils. Thus we investigated whether pretreatment of neutrophils with GM‐CSF would prime subsequent chemotaxis to IL‐8 in the absence of GM‐CSF. Surprisingly, a 3‐hr pulse of GM‐CSF severely diminished chemotaxis to IL‐8, whereas N‐formyl‐methyl‐leucyl‐phenylalanine (fMLP)‐mediated chemotaxis was retained. Conversely, when cells were incubated without GM‐CSF they retained IL‐8‐mediated migration but lost fMLP chemotaxis. These changes in chemotaxis did not correlate with expression of CXCR1, CXCR2 or formyl peptide receptor. However, IL‐8‐mediated phosphorylation of p44/42 mitogen‐activated protein kinase was greatly reduced in neutrophils that no longer migrated to IL‐8, and was diminished in cells that no longer migrated to fMLP. Oestradiol, which is reported by some to exert an anti‐inflammatory effect on neutrophils, did not change the effects of GM‐CSF. These data suggest that neutrophil function may be altered by cytokines such as GM‐CSF through modulation of signalling and independently of surface receptor expression.

Human fallopian tube neutrophils--a distinct phenotype from blood neutrophils.

Problem  The role of neutrophils in the human Fallopian tube (FT) is unknown. In order to provide insights into their functions in the FT, we systematically compared neutrophils from normal FT and peripheral blood (PB).

Serotyping group B streptococci in a small community hospital: an analysis of distribution and site of isolation

OBJECTIVE: To determine the prevalence and site of isolation of different serotypes of group B streptococcus (GBS) colonization or infection at a small community hospital. METHODS: GBS isolates were obtained from a small community hospital and were then serotyped as la, Ib, II, III, IV, V or nontypeable. Hospital records were reviewed for patient sex, age and pregnancy status as well as the site of GBS isolation. RESULTS: GBS serotypes Ia, III and V were most common and accounted for over 60% of the total number of isolates. Serotype Ia was most prevalent in reproductive-age females, while serotypes V and III were most prevalent in non-reproductive-age females and males, respectively. Serotype la was most frequent in both pregnant and nonpregnant females. Serotype IV was more common in this study population than in those from other locations. CONCLUSIONS: The GBS serotype distribution in this small community did not differ significantly from distributions described in larger North American centers. A GBS vaccine designed against multiple serotypes would be protective for most of this population.