Background: The combination antiretroviral therapy (cART) could increase the number
of circulating naive CD4 T lymphocytes, but was not able to eradicate human immunodeficiency
virus-1 (HIV-1) infection.
Objective: Thus, induction of strong immune responses is important for control of HIV-1 infection.
Furthermore, a simple and perfect serological method is required to detect virus in untreated-, treated-
and drug resistant- HIV-1 infected individuals.
Methods: This study was conducted to assess and compare immunogenic properties of Nef, Vif,
Vpr and Vpu accessory proteins as an antigen candidate in mice and their diagnostic importance in
human as a biomarker.
Results: Our data showed that in mice, all heterologous prime/ boost regimens were more potent
than homologous prime/ boost regimens in eliciting Th1 response and Granzyme B secretion as
CTL activity. Moreover, the Nef, Vpu and Vif proteins could significantly increase Th1 immune response.
In contrast, the Vpr protein could considerably induce Th2 immune response. On the other
hand, among four accessory proteins, HIV-1 Vpu could significantly detect treated group from untreated
group as a possible biomarker in human.
Conclusion: Generally, among accessory proteins, Nef, Vpu and Vif antigens were potentially
more suitable vaccine antigen candidates than Vpr antigen. Human antibodies against all these proteins
were higher in HIV-1 different groups than healthy group. Among them, Vpu was known as a
potent antigen in diagnosis of treated from untreated individuals. The potency of accessory proteins
as an antigen candidate in an animal model and a human cohort study are underway.