HIV-1-specific mucosal IgA in a cohort of HIV-1-resistant Kenyan sex workers.
OBJECTIVE
Most HIV-1 transmission is sexual; therefore, immune responses in the genital mucosa may be important in mediating protection against HIV infection. This study examined HIV-1-specific mucosal IgA in a cohort of HIV-1-resistant Kenyan female sex workers.


METHODS
HIV-1-specific immune responses were compared in HIV-1-resistant and HIV-1-infected sex workers, and in lower risk uninfected women. Cervical and vaginal samples from each group were tested for HIV-1-specific IgA and IgG by enzyme immunoassay. Systemic T-helper lymphocyte cell responses to HIV-1 envelope peptide epitopes were assayed using an interleukin 2 bioassay. HIV-1 risk-taking behaviours were assessed using standardized questionnaires.


RESULTS
HIV-1-specific IgA was present in the genital tract of 16 out of 21 (76%) HIV-1-resistant sex workers, five out of 19 (26%) infected women, and three out of 28 (11%) lower risk women (P < 0.0001). Among lower risk women, the presence of HIV-1-specific IgA was associated with HIV-1 risk-taking behaviour. Systemic T-helper lymphocyte responses to HIV-1 envelope peptides were present in 11 out of 20 (55%) HIV-1-resistant women, four out of 18 (22%) infected women, and one out of 25 (4%) lower risk women (P < 0.001). T-helper lymphocyte responses did not correlate with the presence or titre of virus-specific mucosal IgA in any study group.


CONCLUSIONS
HIV-1-specific IgA is present in the genital tract of most HIV-1-resistant Kenyan sex workers, and of a minority of lower risk uninfected women, where it is associated with risk-taking behaviour. These data suggest a role for mucosal HIV-1-specific IgA responses in HIV-1 resistance, independent of host cellular responses.
Kaul
R
R
Department of Medical Microbiology and Community Health, University of Nairobi, Kenya.
Trabattoni
D
D
Bwayo
J J
JJ
Arienti
D
D
Zagliani
A
A
Mwangi
F M
FM
Kariuki
C
C
Ngugi
E N
EN
MacDonald
K S
KS
Ball
T B
TB
Clerici
M
M
Plummer
F A
FA
D018791:CD4 Lymphocyte Count; D002584:Cervix Uteri / Q000276:immunology*; D015331:Cohort Studies; D005260:Female; D015483:HIV Antibodies / Q000276:immunology*; D015658:HIV Infections / Q000453:epidemiology / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D007070:Immunoglobulin A / Q000276:immunology*; D007074:Immunoglobulin G; D007630:Kenya / Q000453:epidemiology; D009092:Mucous Membrane / Q000276:immunology; D011477:Sex Work; D014621:Vagina / Q000276:immunology*
D015483:HIV Antibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G