HLA class II restriction of HIV-1 clade-specific neutralizing antibody responses in ethnic Thai recipients of the RV144 prime-boost vaccine combination of ALVAC-HIV and AIDSVAX(®) B/E.

Immune responses to vaccines may be influenced or associated with allelic variants of host genes such as those encoding human leucocyte antigens (HLA). We have molecularly determined the HLA class II DR and DQ gene, allele and haploype profiles in HIV-1 negative ethnic Thai recipients of an HIV-1 prime boost vaccine regimen, designed to induce neutralizing antibody (NAb) responses to HIV-1 CRF01_AE. Non-response to vaccine associated with DRB111 (3/32 responders vs. 7/13 non-responders, p(c)=0.027) and DRB116:02 (0/32 responders vs. 4/13 non-responders, p(c)=0.078) alleles. Furthermore, vaccine recipients with HLA-DQ heterodimers encoded by DQA105:01 and DQB103:01 alleles, were much less likely to produce NAb (p=0.009). These data suggest that the lack of response to a vaccine designed to induce clade-specific NAb to HIV-1 is associated with the presence of certain HLA class II alleles and heterodimers in some Southeast Asians.