Individual differences in susceptibility to human immunodeficiency virus type 1 (HIV-1) infection have been of
interest for decades. We aimed to determine the contribution of large isoform of Mammalian DnaJ (MRJ-L), a
HIV-1 Vpr-interacting cellular protein, to this natural variation. Expression ofMRJ-L in monocyte-derived macrophages
was significantly higher in HIV-infected individuals (n=31) than their uninfected counterparts (n=27)
(p= 0.009). Fifty male homosexual subjects (20 of them are HIV-1 positive) were further recruited to examine
the association between MRJ-L levels and occurrence of HIV infection. Bayesian multiple logistic regression revealed
that playing a receptive role and increased levels of MRJ-L in macrophages were two risk factors for
HIV-1 infection. A 1% rise in MRJ-L expression was associated with a 1.13 fold (95% CrI 1.06–1.29) increase in
odds of contracting HIV-1 infection. Ex vivo experiments revealed that MRJ-L facilitated Vpr-dependent nuclear
localization of virus. Infection ofmacrophage-tropic strain is a critical step in HIV-1 transmission.MRJ-L is a critical
factor in this process; hence, subjects with higher macrophage MRJ-L levels are more vulnerable to HIV-1
infection.