e HIV “1446712 had significantly lower levels of SLPI. Cationic polypeptides contribute substantially to the HIV-neutralizing activity of CVS from HIV seronegative individuals In this set of experiments, we explored the HIV-neutralizing activity of the cationic polypeptide components of CVS from HIV seronegative women. A total of 14 CVS samples were selected for the presence of intrinsic HIV neutralizing activity and Indirubin-3′-oxime site pooled into three groups to reach sufficient volume for the following experiments. First, the cationic polypeptides were selectively removed from the CVS pools while sparing the concentrations of remaining proteins and electrolytes. The complete removal of cationic polypeptides was confirmed by AU-PAGE for all pools. The cationic polypeptide fractions were then tested for HIV neutralizing activity, and each fraction had activity equivalent to that of the whole pool. The remaining peptide-depleted CVS samples had no HIV neutralizing activity. Thus, the majority of the functional activity seems to be mediated by the cationic polypeptide fraction. Levels of cationic polypeptides in relation to presence or absence of PSA in the CVS samples To evaluate the influence of seminal contamination in the CVS, samples were assessed for presence of PSA and then compared for levels of cationic polypeptides. PSA was found in 33% of the CVS samples representing the low-risk group followed by 12% in the HIV positive group and 10% in the HESN group. Assessing all study groups together, no statistically significant differences were seen between PSA positive and PSA negative CVS samples for levels of HNP13. Levels of LL-37 were however significantly lower among the PSA positive versus the PSA negative CVS samples, whereas levels of SLPI were significantly higher among the PSA positive versus the PSA negative CVS samples. Reanalysing the data presented in Recombinant cationic polypeptides can augment the intrinsic HIV-neutralizing activity of CVS from HIV low-risk women Next we studied whether adding individual recombinant cationic polypeptides to CVS could induce HIV neutralizing activity. Theoretically, the added peptides would act synergistically with other innate immune factors naturally present in CVS. For these experiments, CVS from HIV seronegative women lacking intrinsic HIV neutralizing activity were selected and the HIV neutralizing assay was adapted to establish the ratio between peptide+CVS versus medium+CVS. SLPI as well as recombinant HNP13 and LL-37 were evaluated in three independent experiments. As a result, both HNP13 and LL-37 induced a two to six-fold increase of HIV inhibiting activity when assessed at about “2568146 1050 times the physiological concentrations, whereas the effect of SLPI was only marginal. At physiological concentrations, no effect was seen for any of the peptides. 
Discussion We document here the presence of cationic polypeptides and intrinsic HIV neutralizing activity in CVS of Kenyan women who are HIV infected, HESN, and HIV-uninfected low risk. The three cationic polypeptides HNP13, LL-37 and SLPI were selected for assessment because they were previously shown to be important mediators of HIV neutralization in vitro, and because they are detectable in cervicovaginal lavage from healthy women. Although presence of HIV neutralizing activity did not associate directly with individual levels of HNP13 or LL-37, it was clearly correlated with the whole cationic polypeptide fraction of CVS. This correlation was shown in vitro by