PrEP interest and HIV-1 incidence among MSM and transgender women in coastal Kenya

INTRODUCTION

There is emerging data on HIV-1 incidence among MSM in sub-Saharan Africa (SSA), but no known estimate of HIV-1 incidence among transgender women (TGW) in the region has yet been reported. We assessed HIV-1 incidence and pre-exposure prophylaxis (PrEP) interest in men who have sex with men exclusively (MSME), men who have sex with men and women (MSMW) and TGW in coastal Kenya.

METHODS

HIV-1-seronegative individuals who had participated in an HIV testing study in 2016 were traced and retested in 2017 according to Kenyan guidelines. All participants were assigned male sex at birth and had male sex partners; additional data on gender identity and sexual orientation were obtained. We assessed the factors associated with HIV-1 acquisition using Poisson regression and calculated HIV-1 incidence in MSME, MSMW and TGW. PrEP interest was assessed through focus group discussions to characterize subcategories' perceived PrEP needs.

RESULTS

Of the 168 cohort participants, 42 were classified as MSME, 112 as MSMW and 14 as TGW. Overall, HIV-1 incidence was 5.1 (95% confidence interval (CI): 2.6 to 9.8) per 100 person-years (PY): 4.5 (95% CI: 1.1 to 17.8] per 100 PY among MSME, 3.4 (95% CI: 1.3 to 9.1) per 100 PY among MSMW and 20.6 (95% CI: 6.6 to 63.8] per 100 PY among TGW. HIV-1 acquisition was associated with exclusive receptive anal intercourse (aIRR 13.0, 95% CI 1.9 to 88.6), history of an STI in preceding six months (aIRR 10.3, 95% CI 2.2 to 49.4) and separated/divorced marital status (aIRR 8.2 (95%: 1.1 to 62.2). Almost all (98.8%) participants were interested in initiating PrEP. MSME and TGW felt that PrEP would lead to increases in condomless anal or group sex.

CONCLUSIONS

TGW had a very high HIV-1 incidence compared with MSME and MSMW. Subcategories of MSM anticipated different PrEP needs and post-PrEP risk behaviour. Further studies should assess if TGW may have been wrongly categorized as MSM in other HIV-1 incidence studies in the region.

The E6 variant proteins E6I-E6IV of human papillomavirus 16: expression in cell free systems and bacteria and study of their interaction with p53

Several species of alternatively spliced mRNAs are transcribed from the E6 gene region of human papillomavirus (HPV) 16. These have the coding capacity for either the full length E6 of 151 amino acids (aa) or four truncated variants, E6I-E6IV, of 43-64 aa. As the first step to identify the putative E6 variants and their functions, we generated cDNAs corresponding to the various E6 open reading frames (ORF) and examined their expression employing in vitro transcription/translation systems and the bacterial pET system. In wheat germ extract, in vitro translation resulted in the production of all five proteins, E6 and E6I-E6IV. These proteins were also expressed as stable fusion proteins from the pET16b and pET17 x b vectors in Escherichia coli. Mobilites of the E6 variant proteins on SDS-acrylamide gels were consistent with their predicted sizes. The authenticity of the synthesized proteins was confirmed by immunoprecipitation with specific antibodies directed against epitopes in the N-terminal portion of E6 as well as antibodies raised against the individual variant proteins produced in E. coli. In rabbit reticulocyte lysate, however, only the full length E6 and the E6IV variant were synthesized. This could be due to inefficient translation as well as lower stability of the short variants. E6I-III, in reticulocyte lysate (RTL). The ability of the E6 variants to associate with p53 and target its proteolytic degradation in vitro, was examined in coimmunoprecipitation assays, using in vitro synthesized proteins and monoclonal antibodies to p53. Results of these assays indicated that only the full length E6 efficiently binds to and promotes the degradation of p53. The E6 variants E6I-E6IV, although able to associate with p53 at a low efficiency, were unable to target its degradation.