Methamphetamine decreases CD4 T cell frequency and alters pro-inflammatory cytokine production in a model of drug abuse.

The reason co-morbid methamphetamine use and HIV infection lead to more rapid progression to AIDS is unclear. We used a model of methamphetamine self-administration to measure the effect of methamphetamine on the systemic immune system to better understand the co-morbidity of methamphetamine and HIV. Catheters were implanted into the jugular veins of male, Sprague Dawley rats so they could self-administer methamphetamine (n=18) or be given saline (control; n=16) for 14 days. One day after the last operant session, blood and spleens were collected. We measured serum levels of pro-inflammatory cytokines, intracellular IFN-γ and TNF-α, and frequencies of CD4(+), CD8(+), CD200(+) and CD11b/c(+) lymphocytes in the spleen. Rats that self-administered methamphetamine had a lower frequency of CD4(+) T cells, but more of these cells produced IFN-γ. Methamphetamine did not alter the frequency of TNF-α-producing CD4(+) T cells. Methamphetamine using rats had a higher frequency of CD8(+) T cells, but fewer of them produced TNF-α. CD11b/c and CD200 expression were unchanged. Serum cytokine levels of IFN-γ, TNF-α and IL-6 in methamphetamine rats were unchanged. Methamphetamine lifetime dose inversely correlated with serum TNF-α levels. Our data suggest that methamphetamine abuse may exacerbate HIV disease progression by activating CD4 T cells, making them more susceptible to HIV infection, and contributing to their premature demise. Methamphetamine may also increase susceptibility to HIV infection, explaining why men who have sex with men (MSM) and frequently use methamphetamine are at the highest risk of HIV infection.

Development of IgG Mediated Antibody Dependent Cell-mediated Cytotoxicity (ADCC) in the Serum and Genital Mucosa of HIV Seroconverters.

BACKGROUND: We measured antibody-dependent cell mediated cytotoxicity (ADCC) activity in serum and genital fluids of heterosexually exposed women during HIV seroconversion. METHODS: Plasma and cervico-vaginal lavage (CVL) fluid from 11 seroconverters (SC) were analyzed biannually from one year pre- to 6 year post-seroconversion using a 51Cr-release assay to measure HIV-1 gp120 specific ADCC. RESULTS: No SC had significant HIV specific CVL ADCC activity before seroconversion or until 1.5 yr after seroconversion. One individual had a %Specific Release (SR) of 25.4 at 2 years, 26.7 at 3 years and 21.0 at 4 years after seroconversion in CVL. Another sample had 4.7% SR at 2 years, 5.3 at 3 years, 10.9 at 4 years, and 8.4 at 5 years after seroconversion in CVL. A third had no activity until 17% SR 5 years after seroconversion in CVL. A fourth showed activity of 36.5% SR at 6.5 years after seroconversion. Seven women had no ADCC activity in their CVL. Paired serum samples showed HIV specific ADCC activity prior to the appearance of CVL ADCC activity. CONCLUSIONS: HIV specific ADCC activity in CVL rose 2 years after seroconversion; ADCC was present in the serum prior to this time. These data suggest that genital tract ADCC activity is not present until well after acute infection.

Effects of cryopreservation on effector cells for antibody dependent cell-mediated cytotoxicity (ADCC) and natural killer (NK) cell activity in (51)Cr-release and CD107a assays.

Freshly isolated PBMC are broadly used as effector cells in functional assays that evaluate antibody-dependent cell mediated cytotoxicity (ADCC) and NK activity; however, they introduce natural-individual donor-to-donor variability. Cryopreserved PBMC provide a more consistent source of effectors than fresh cells in cytotoxicity assays. Our objective was to determine the effects of cryopreservation of effector PBMC on cell frequency, and on the magnitude and specificity of ADCC and NK activity. Fresh, frozen/overnight rested and frozen/not rested PBMC were used as effector cells in (51)Cr-release and CD107a degranulation assays. Frozen/overnight rested PBMC had higher ADCC and NK activity in both assays when compared to fresh PBMC; however, when using frozen/not rested PBMC, ADCC and NK activities were significantly lower than fresh PBMC. Background CD107a degranulation in the absence of target cell stimulation was greater in PBMC that were frozen/not rested when compared to fresh PBMC or PBMC that were frozen overnight and rested. The percentages of CD16(+)CD56(dim) NK cells and CD14(+) monocytes were lower in PBMC that were frozen and rested overnight than in fresh PBMC. CD16 expression on CD56(dim) NK cells was similar for all PBMC treatments. PBMC that were frozen and rested overnight were comparable to fresh PBMC effectors. PBMC that were frozen and used immediately when evaluating ADCC or NK activity using either a (51)Cr-release assay or a CD107a degranulation assay had the lowest activity. Clinical studies of antibodies that mediate ADCC would benefit from using effector cells that have been frozen, thawed and rested overnight prior to assay.

A novel human antimicrobial factor targets Pseudomonas aeruginosa through its type III secretion system.

Pseudomonas aeruginosa is an important opportunistic bacterial pathogen. Despite its metabolic and virulence versatility, it has not been shown to infect articular joints, which are areas that are rarely infected with bacteria in general. We hypothesized that articular joints possess antimicrobial activity that limits bacterial survival in these environments. We report that cartilages secrete a novel antimicrobial factor, henceforth referred to as the cartilage-associated antimicrobial factor (CA-AMF), with potent antimicrobial activity. Importantly, CA-AMF exhibited significantly more antimicrobial activity against P. aeruginosa strains with a functional type III secretion system (T3SS). We propose that CA-AMF represents a new class of human antimicrobial factors in innate immunity, one which has evolved to selectively target pathogenic bacteria among the beneficial and commensal microflora. The T3SS is the first example, to the best of our knowledge, of a pathogen-specific molecular target in this antimicrobial defence system.