Recent investigations suggest that the retroviruses Human T-Cell Leukemia Virus (HTLV-III) and Lymphadenopathy Associated Virus (LAV) may be the agents (or agent, if they prove to be identical) responsible for AIDS (Centers for Disease Control, 1984). Large-scale production techniques to produce virus and virus antigens in sufficient quantities to develop diagnostic kits for detection of antibody already are under licensure from the National Institutes of Health (NIH) to at least five commercial companies. Panels of scientists at the NIH and the Food and Drug Administration are proceeding as rapidly as possible with studies of the relevant etiologic relationships, and their results could provide the information necessary to begin development of possible vaccines.
Consideration of a candidate AIDS vaccine under the formula developed by the Committee would be influenced markedly by the high mortality rate associated with AIDS as studied to date. Two years after diagnosis, more than 70 percent of patients have died. Estimates indicate that the total number of persons affected is now about 5,000.
The availability of stable cell lines and a lymphoblastoid cell line in which HTLV-III and LAV replicate further augments the capacity for vaccine development. Robert Gallo and his colleagues at the National Cancer Institute have suggested that analysis of a specific viral protein antigen, common to all HTLV-III isolates examined to date, might be a suitable beginning for research leading to a possible vaccine. It is important to remember that previous attempts to prepare immunizing agents against animal retroviruses have not been very successful, but they have never been fully exploited. AIDS, if it is indeed a human retrovirus-induced disorder, certainly will provide the incentive necessary for new work in this area.
Live virus vaccines seem unlikely with agents so readily integrated into the host cell genome. Inactivated virus or component antigens are promising and certainly should be safe. Eventual decisions regarding investment in vaccine development obviously would include consideration of a number of the factors discussed in Chapter 8, “Additional issues in the Selection of Priorities for Accelerated Vaccine Development.”
Adenovirus causes acute respiratory disease in children and military recruits, gastrointestinal disease, and conjunctivitis. Efforts to produce vaccines for these illnesses have been reviewed briefly by Foy and Grayston (1982).
Early work involving inactivated vaccines for military recruits encountered problems with variable vaccine potency, which resulted from poor virus growth in the monkey cell cultures used for propagation. Other researchers have shown that subunit vaccines are possible (Kasel et al., 1966), but both of these approaches have been abandoned in favor of attempts to stimulate immunity to respiratory infection with live oral vaccines.
Multivalent live oral vaccines are licensed for the strains responsible for disease in military recruits, but these are different from