Greg T. Spear

Characterization of viral dynamics in human immunodeficiency virus type 1-infected patients treated with combination antiretroviral therapy: relationships to host factors, cellular restoration, and virologic end points.

Biphasic plasma viral decays were modeled in 48 patients treated with ritonavir, zidovudine, and lamivudine. Estimated first- and second-phase decay rates were d1 as 0.47/day and d2 as 0.04/day. Interpatient differences in both decay rates were significant. The d1 was directly correlated with baseline CD4+, CD4+CD28+, and CD8+CD28+ T lymphocyte counts (P<.05) and inversely correlated with baseline virus load (P=.044) and the magnitude of CD4+ and CD8+ T lymphocyte recovery (P<.01). The d2 was directly correlated with baseline percentage of CD8+ T lymphocytes (P=.023), the CD8+CD38+ cell number (P=.024), and the level of IgG that binds to human immunodeficiency virus (HIV) type 1 gp120 (P=.02). Viral decay rates were not predictive of treatment failure or durability of viral suppression. These exploratory findings are consistent with a model in which immunologic factors contribute to elimination of HIV-infected cells and suggest a dynamic interplay between regulation of HIV expression and lymphocyte activation and recovery.

The effects of commensal bacteria on innate immune responses in the female genital tract.

Citation 
Mirmonsef P, Gilbert D, Zariffard MR, Hamaker BR, Kaur A, Landay AL, Spear GT. The effects of commensal bacteria on innate immune responses in the female genital tract. Am J Reprod Immunol 2011; 65: 190–195

Short Chain Fatty Acids Induce Pro-Inflammatory Cytokine Production Alone And In Combination With Toll-like Receptor Ligands

Citation Mirmonsef P, Zariffard MR, Gilbert D, Makinde H, Landay, AL, Spear GT. Short‐chain fatty acids induce pro‐inflammatory cytokine production alone and in combination with Toll‐like receptor ligands. Am J Reprod Immunol 2012; 67: 391–400

Synovial fluid from patients with early osteoarthritis modulates fibroblast‐like synoviocyte responses to Toll‐like receptor 4 and Toll‐like receptor 2 ligands via soluble CD14

OBJECTIVE Synovial inflammation, a feature of both osteoarthritis (OA) and meniscal injury, is hypothesized to be triggered in part via stimulation of Toll-like receptors (TLRs). We undertook this study to test whether a TLR-2- or TLR-4-stimulating factor in synovial fluid (SF) from patients with early knee OA with meniscal injury could lead to inflammatory activation of synoviocytes. METHODS SF was obtained from patients with early OA cartilage damage undergoing arthroscopic meniscal procedures. SF was used to stimulate primary cultures of fibroblast-like synoviocytes (FLS) and cell lines transfected with TLR-2 or TLR-4. SF was used either alone or in combination with a TLR-2 stimulus (palmitoyl-3-cysteine-serine-lysine-4 [Pam3CSK4]) or a TLR-4 stimulus (lipopolysaccharide [LPS]). In blocking experiments, SF was preincubated with anti-CD14 antibody. RESULTS SF from these patients did not stimulate interleukin-8 (IL-8) release from TLR transfectants. Compared with SF on its own, SF (at concentrations of 0.09-25%) in combination with TLR-2 or TLR-4 ligands resulted in significant augmentation of IL-8 release from both transfectants and primary FLS. Soluble CD14 (sCD14), a coreceptor for TLRs, was measured in SF from patients with early OA at levels comparable to those in patients with advanced OA and patients with rheumatoid arthritis. Blockade with anti-CD14 antibody abolished the ability of SF to augment IL-8 production in response to LPS, and diminished Pam3CSK4 responses. CONCLUSION SF augments FLS responses to TLR-2 and TLR-4 ligands. This effect was largely due to sCD14. Our results demonstrate that sCD14 in the setting of OA and meniscal injury sensitizes FLS to respond to inflammatory stimuli such as TLR ligands.

Evaluation of immunologic markers in cervicovaginal fluid of HIV-infected and uninfected women: implications for the immunologic response to HIV in the female genital tract.

We analyzed 21 cervicovaginal lavage (CVL) specimens from 19 women participating in the Womens Interagency HIV Study to characterize levels of antibody, cytokine, and complement and to determine associations between these levels and stage of the menstrual cycle, HIV status, and the presence of concurrent genital infection and genital dysplasia. Sixteen samples were collected from HIV-infected women and five from high-risk HIV-seronegative women. CVL fluid was assayed for levels of IgG, secretory IgA (s-IgA), interleukin 2 (IL-2), IL-10, IL-6, tumor necrosis factor alpha (TNF-alpha), IL-1beta, interferon gamma (IFN-gamma), C3, C1q, and C4. Women with HIV were more likely to have cervicovaginal dysplasia (9/16 vs. 0/5; p = 0.027) but were not more likely to have concurrent vaginal infection (10/16 vs. 2/5; p = 0.38). Antibody, cytokine, and complement were detectable in all samples, although not all samples had measurable IL-10, C3, or C4. HIV-infected women demonstrated a trend toward higher levels of IFN-gamma than did uninfected women (p = 0.098); no differences were noted in other parameters. HIV-infected women with vaginal infections had significantly higher CVL levels of IgG (p = 0.023) and IFN-gamma (p = 0.02) than did HIV-infected women without genital infections. HIV-infected women with cervicovaginal dysplasia were found to have higher levels of IL-1beta (p = 0.045) and IFN-gamma (p = 0.039) than those without. Analysis of the HIV-infected cohort by CD4 cell count revealed higher levels of IgG and IFN-gamma in CVL from women with lower CD4 cell counts, although these differences were not statistically significant. Higher levels of proinflammatory cytokines in CVL fluid of women with genital infection or cervicovaginal dysplasia may affect local HIV replication and may influence the risk of acquisition or transmission of HIV for women with these underlying conditions.

Exploratory comparison of vaginal glycogen and Lactobacillus levels in premenopausal and postmenopausal women.

ObjectivePrevious studies have suggested that glycogen expression in the vaginal epithelium decreases during menopause, resulting in reduced levels of lactobacilli. However, free glycogen in genital fluids and its relationship with Lactobacillus levels have not been compared in premenopausal and postmenopausal women. MethodsEighty-two cervicovaginal lavage samples were collected at different phases of the menstrual cycle from 11 premenopausal (4 HIV-uninfected and 7 HIV-infected) and 12 postmenopausal (7 HIV-uninfected and 5 HIV-infected) women during a 1- to 3-month period. Free glycogen was quantified in genital fluids. Lactobacillus levels were quantified by real-time polymerase chain reaction. Estrogen and progesterone levels in blood were determined by enzyme-linked immunosorbent assay. ResultsFree glycogen was detected in both premenopausal and postmenopausal women. Across all samples, those from postmenopausal women had significantly lower levels of free glycogen than those from premenopausal women (median, 0.002 vs 0.065 &mgr;g/&mgr;L, respectively; P = 0.03). Lactobacillus levels correlated positively with free glycogen in both premenopausal (Spearman r = 0.68, P < 0.0001) and postmenopausal (r = 0.60, P < 0.002) women. Samples from premenopausal women had higher Lactobacillus levels and lower vaginal pH (median log, 8.1; median pH, 4) than those from postmenopausal women (median log, 7.1; median pH, 4.6), although these differences were not significant. HIV status had no significant effect on these relationships. ConclusionsFree glycogen is detected in both premenopausal and postmenopausal women and correlates with Lactobacillus in both groups. These results point to the complexity of the relationship between menopause and vaginal microbiota and indicate that more careful studies of the role of glycogen are warranted.

Chemokines are present in the genital tract of HIV-seropositive and HIV-seronegative women: correlation with other immune mediators.

In this cross-sectional study, 53 cervicovaginal lavage samples (CVL) from 41 women were analyzed for the chemokines interleukin-8 (IL-8), regulated-on-activation normal T-expressed and secreted (RANTES) factor, and macrophage inflammatory protein-1alpha (MIP-1alpha) by enzyme-linked immunosorbent assay (ELISA). IL-8 was detected in 81% of CVL, whereas RANTES was detected in 32%, and MIP-1alpha in 15% of the CVL. The mean levels of IL-8, RANTES, and MIP-1alpha in positive samples were 396 pg/ml, 102 pg/ml, and 34 pg/ml, respectively. IL-8 levels correlated positively with IL-1beta and IgG in a subset of CVL samples. RANTES levels correlated positively with complement protein levels. Additionally, the levels of RANTES, but not MIP-1alpha, reached levels reported in previous studies of the effects of beta chemokines to inhibit HIV replication. These results suggest that measuring chemokines in CVL specimens can provide important information regarding immune responses in the genital tract.

Microbial Diversity of Genital Ulcer Disease in Men Enrolled in a Randomized Trial of Male Circumcision in Kisumu, Kenya

Background Medical male circumcision (MMC) reduces the risk of genital ulcer disease (GUD) in men by 50%. In Ugandan and Kenyan trials, a sexually transmissible agent was not identified in 50–60% of GUD specimens by polymerase chain reaction (PCR) assay. We sought to better define the etiology of GUD in men participating in the Kenyan trial and examine how MMC affects GUD etiology. Methods We defined GUD of unknown etiology as negative for HSV (type 1 and type 2), T. pallidum, and H. ducreyi by PCR, and negative for HSV-2 and T. pallidum by serology. We identified bacterial microbiota in a subset of 59 GUD specimens using multitag pyrosequencing of the 16S rRNA gene, and compared results by unknown vs. STI-associated etiology. Statistical analysis employed Bray-Curtis similarity measure of bacterial community by etiology, hierarchical clustering and logistic regression. Results In 59 GUD specimens from 59 men, 23 (39%) had unknown etiology. Bacterial diversity was greater in GUD of unknown than STI etiology (p = 0.01). Fusobacteria (Fusobacterium spp. and Sneathia spp.) were more commonly detected in men with GUD of unknown etiology [adjusted OR = 5.67; 95% CI: 1.63–19.8] as were Oxobacter spp. and Anaerovorax spp. [adjusted OR = 3.12; 95% CI: 0.83–11.7]. Sequences from these four anaerobic bacterial taxa were more often detected in uncircumcised men than circumcised men (p<0.05). Conclusions Anaerobic bacteria are more common in genital ulcers of uncircumcised men. The specific anaerobic bacteria associated with GUD of unknown etiology have cytotoxic properties that can exacerbate epithelial disruptions leading to ulcer-like appearance. MMC may reduce GUD through a reduction in these anaerobic bacteria.

The Vaginal Microbiota over an 8- to 10-Year Period in a Cohort of HIV-Infected and HIV-Uninfected Women

Background We identified predominant vaginal microbiota communities, changes over time, and how this varied by HIV status and other factors in a cohort of 64 women. Methods Bacterial DNA was extracted from reposited cervicovaginal lavage samples collected annually over an 8–10 year period from Chicago Women’s Interagency HIV Study participants: 22 HIV-negative, 22 HIV-positive with stable infection, 20 HIV-positive with progressive infection. The vaginal microbiota was defined by pyrosequencing of the V1/V2 region of the 16S rRNA gene. Scheduled visits included Bacterial vaginsosis (BV) screening; clinically detected cases were referred for treatment. Hierarchical clustering identified bacterial community state types (CST). Multinomial mixed effects modeling determined trends over time in CST, by HIV status and other factors. Results The median follow-up time was 8.1 years (range 5.5–15.3). Six CSTs were identified. The mean relative abundance (RA) of Lactobacillus spp. by CST (with median number of bacterial taxa) was: CST-1–25.7% (10), CST-2–27.1% (11), CST-3–34.6% (9), CST-4–46.8% (9), CST-5–57.9% (4), CST-6–69.4% (2). The two CSTs representing the highest RA of Lactobacillus and lowest diversity increased with each additional year of follow-up (CST-5, adjusted odds ratio (aOR) = 1.62 [95% CI: 1.34–1.94]; CST-6, aOR = 1.57 [95 CI: 1.31–1.89]), while the two CSTs representing lowest RA of Lactobacillus and higher diversity decreased with each additional year (CST-1, aOR = 0.89 [95% CI: 0.80–1.00]; CST-2, aOR = 0.86 [95% CI: 0.75–0.99]). There was no association between HIV status and CST at baseline or over time. CSTs representing lower RA of Lactobacillus were associated with current cigarette smoking. Conclusions The vaginal microbial community significantly improved over time in this cohort of women with HIV and at high risk for HIV who had regular detection and treatment referral for BV.

Effect of pH on Cleavage of Glycogen by Vaginal Enzymes.

Glycogen expressed by the lower genital tract epithelium is believed to support Lactobacillus growth in vivo, although most genital isolates of Lactobacillus are not able to use glycogen as an energy source in vitro. We recently reported that α-amylase is present in the genital fluid of women and that it breaks down glycogen into small carbohydrates that support growth of lactobacilli. Since the pH of the lower genital tract can be very low, we determined how low pH affects glycogen processing by α-amylase. α-amylase in saliva degraded glycogen similarly at pH 6 and 7, but activity was reduced by 52% at pH 4. The glycogen degrading activity in nine genital samples from seven women showed a similar profile with an average reduction of more than 50% at pH 4. However, two samples collected from one woman at different times had a strikingly different pH profile with increased glycogen degradation at pH 4, 5 and 6 compared to pH 7. This second pH profile did not correlate with levels of human α-acid glucosidase or human intestinal maltase glucoamylase. High-performance anion-exchange chromatography showed that mostly maltose was produced from glycogen by samples with the second pH profile in contrast to genital α-amylase that yielded maltose, maltotriose and maltotetraose. These studies show that at low pH, α-amylase activity is reduced to low but detectable levels, which we speculate helps maintain Lactobacillus growth at a limited but sustained rate. Additionally, some women have a genital enzyme distinct from α-amylase with higher activity at low pH. Further studies are needed to determine the identity and distribution of this second enzyme, and whether its presence influences the makeup of genital microbiota.