Constitutive host factors that influence progression to AIDS are understood poorly. In the macaque model for AIDS, 35 animals infected with simian immunodeficiency virus (SIV) were analyzed for major histocompatibility complex class II antigen expression on blood monocytes and B cells by immunostaining and flow cytometry. Expression varied widely between animals but was constant with time. Level of expression and the proportion of monocytes and B cells that expressed class II were not affected by SIV infection. Significantly more animals developed AIDS in the group with low class II expression than in the group with high expression (P <.001). Progression to disease was faster in animals that expressed poorly (P <.01), and opportunistic pathogens were more common (P <.05). Thus, the constitutive level of class II antigen expression may be a useful prognostic indicator for human immunodeficiency virus disease in humans and may be an important factor in the design of vaccine trials.
Bibliographical noteFunding Information:
Received 24 January 1995; revised 19 May 1995. Presented in part: 11th Annual Symposium on Nonhuman Primate Models for AIDS, Madison, Wisconsin, September 1993; Medical Research Council AIDS-Directed Programme Workshop, Brighton, United Kingdom, September 1993. Financial support: Public Health Laboratory Service, AIDS-Directed Programme ofthe Medical Research Council, European Union Concerted Action on AIDS in Macaques, and Project European Vaccines against AIDS. Reprints or correspondence: Dr. Graham A. Hall, Centre for Applied Microbiology and Research, Porton Down, Salisbury, Wiltshire SP4 OJG, UK.