Publications by authors named "Landon G Vom Steeg"

Since CD4+ T cells are essential for regulating adaptive immune responses and for long lasting mucosal protection, changes in CD4+ T cell numbers and function are likely to affect protective immunity. What remains unclear is whether CD4+ T cell composition and function in the female reproductive tract (FRT) changes as women age. Here we investigated the changes in the composition and function of CD4+ T cells in the endometrium (EM), endocervix (CX), and ectocervix (ECX) with aging.

View Article and Find Full Text PDF

Daptomycin (DAP), a cyclic anionic lipopeptide antibiotic, is among the last resorts to treat multidrug-resistant Gram-positive bacterial infections, caused by vancomycin-resistant or methicillin-resistant . DAP is administered intravenously, and via biliary excretion, ∼5-10% of the intravenous DAP dose arrives in the gastrointestinal (GI) tract where it drives resistance evolution in the off-target populations of bacteria. Previously, we have shown that the oral administration of cholestyramine, an ion exchange biomaterial (IXB) sorbent, prevents DAP treatment from enriching DAP resistance in the populations of shed from mice.

View Article and Find Full Text PDF

Circulating androgens can modulate immune cell activity, but the impact of androgens on viral pathogenesis remains unclear. Previous data demonstrate that testosterone reduces the severity of influenza A virus (IAV) infection in male mice by mitigating pulmonary inflammation rather than by affecting viral replication. To examine the immune responses mediated by testosterone to mitigate IAV-induced inflammation, adult male mice remained gonadally intact or were gonadectomized and treated with either placebo or androgen-filled (i.

View Article and Find Full Text PDF

The severity of influenza increases with age, with worse disease in aged males than females. Testosterone concentrations decline with age in males, which may impact influenza pathogenesis. Aged male mice were treated with testosterone or placebo and outcomes during influenza A virus (IAV) infection were compared with adult male mice.

View Article and Find Full Text PDF

In both preclinical animal studies and human clinical trials, adult females tend to develop greater adaptive immune responses than males following receipt of either viral or bacterial vaccines. While there is currently no approved malaria vaccine, several anti-sporozoite vaccines, including RTS,S/AS01 and attenuated sporozoite vaccines, are in development, but the impact of sex and age on their efficacy remains undefined. To examine sex differences in the efficacy of anti-sporozoite stage malaria vaccination, adult (10 weeks of age) or juvenile (11 days of age) male and female C3H mice were twice vaccinated with irradiated transgenic Plasmodium berghei sporozoites expressing the P.

View Article and Find Full Text PDF

Males and females differ in the outcome of influenza A virus (IAV) infections, which depends significantly on age. During a typical seasonal influenza epidemic, young children (< 10 years of age) and aged adults (65+ years of age) are at greatest risk for severe disease, and among these age groups, males tend to suffer a worse outcome from IAV infection than females. Following infection with either pandemic or outbreak strains of IAVs, females of reproductive ages (i.

View Article and Find Full Text PDF

Background: Amphiregulin (AREG) is an epidermal growth factor that is a significant mediator of tissue repair at mucosal sites, including in the lungs during influenza A virus (IAV) infection. Previous research illustrates that males of reproductive ages experience less severe disease and recover faster than females following infection with IAV.

Methods: Whether males and females differentially produce and utilize AREG for pulmonary repair after IAV infection was investigated using murine models on a C57BL/6 background and primary mouse and human epithelial cell culture systems.

View Article and Find Full Text PDF

The outcome of microbial infections in mammals, including humans, is affected by the age, sex, and reproductive status of the host suggesting a role for sex steroid hormones. Testosterone, estradiol, and progesterone, signaling through their respective steroid receptors, affect the functioning of immune cells to cause differential susceptibility to parasitic, bacterial, and viral infections. Microbes, including fungi, bacteria, parasites, and viruses, can also use sex steroid hormones and manipulate sex steroid receptor signaling mechanisms to increase their own survival and replication rate.

View Article and Find Full Text PDF

Influenza severity increases with age, with hospitalization and mortality rates during seasonal influenza epidemics being higher in older men than age-matched women. As it is known that with age, circulating testosterone levels decline in males, we hypothesized that reduced testosterone contributes to age-associated increases in influenza severity. A murine model was used to test this hypothesis.

View Article and Find Full Text PDF