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Whole saliva samples collected from available people at risk in Boston for infection with human T-lymphotropic virus type III (HTLV-III/LAV), from late 1984 through early 1985, were analyzed for the presence of antibodies to viral proteins. Fourteen of 20 (70%) acquired immunodeficiency syndrome (AIDS) patients and 14 of 15 (93%) AIDS- related complex (ARC) patients had salivary antibodies that reacted with the virus-encoded glycoproteins gp160 and gp120 of HTLV-III infected cells. All of the AIDS and ARC patients had serum antibodies to the same antigens. Of 20 sex partners of AIDS/ARC patients, nine (45%) showed anti-HTLV-III antibodies, and four of 18 (22%) healthy homosexual males also were positive for such antibodies. Serum and salivary antibody status were the same in these groups. A minority of those patients positive for salivary antibodies to env gene-encoded gp160 and gp120 also had salivary antibodies to gag gene-encoded proteins of 55,000, 24,000, and/or 17,000 daltons. Immunoglobulin A (IgA) class antibodies comprised the majority of the salivary antibody response. The spectrum of HTLV-III proteins detected by the salivary and serum antibodies was similar. The possibility that secretory IgA from the gut-associated lymphoid system may play a role to restrict salivary transmission of HTLV-III should be considered.

Detection methods for the human T-cell leukemia virus type-I (HTLV-I) for blood screening and diagnosis generally rely on antibody tests that use the structural proteins of HTLV-I as antigen. We have found an unusual pattern of antibody reactivity among people who are at high risk of HTLV infection due to being a family member of an adult T-cell leukemia (ATL) patient: a specific antibody reaction exclusively directed to the HTLV regulatory protein tax, and not to the HTLV-I structural proteins. Sera from 7 of 82 (8.5%) structural antibody- undetectable family members of ATL patients had the anti-tax reactivity. Two seroconverters were observed. One seroconverter a healthy resident of Miyazaki, tested negative for structural antibody, but positive for tax antibody. Two years later she tested positive for both. The other seroconverter, an Israeli hemophiliac, tested negative for both antibodies, but converted to tax antibody-positive/structural antibody-negative. The HTLV-I tax-only antibody profile was also observed in sera sets from two other populations at risk for HTLV infection, human immunodeficiency virus-1-infected patients at the Bronx-Lebanon Hospital in New York and Israeli hemophiliacs. DNA samples from lymphocytes of four individuals with antibody reactivity only to HTLV-I tax were tested in polymerase chain reaction experiments; no HTLV-I or -II DNA was detected.

We tested serum samples from 50 hemophiliacs from Sevilla, Spain, for antibody to HTLV-III by indirect membrane immunofluorescence (IMI) and radioimmunoprecipitation with SDS polyacrylamide gel electrophoresis (RIP-SDS/PAGE). All had received commercial clotting factors from the United States with the exception of one hemophiliac who had never been transfused. Thirty-four (68%) reacted with HTLV-III-infected cells (H9/HTLV-III) by both methods, but not with the uninfected line (H9). Of 41 hemophilia-A patients tested, 28 (68%) were positive, and of nine hemophilia-B patients, six (66%) were positive. The nontransfused hemophilia-B patient was negative for antibody to HTLV-III by both methods. One patient with clinical AIDS tested positive as did six of seven with chronic unexplained lymphadenopathy. The eight individuals with AIDS or lymphadenopathy all had hemophilia A. We conclude that exposure to HTLV-III is widespread among asymptomatic hemophiliacs in Spain.

The present studies were initiated to define the coding region of a 34 kilodalton (kd) protein (p34) frequently observed with antibodies from HTLV-III/LAV-infected people by immunoblotting and radioimmunoprecipitation (RIP) techniques. We have directly mapped this viral protein to the pol gene of HTLV-III/LAV by radiolabeled amino acid sequence analysis. This region at the 3' end of the pol gene is predicted to encode the endonuclease/integrase of the virus. The seroprevalence rate of antibodies to the pol gene products p64 and p53 and to the endonuclease p34 were evaluated. Of 161 HTLV-III/LAV seropositive people tested by immunoblotting procedures, greater than 98% had antibodies which reacted to p64/p53 and 92.6% reacted to p34 indicating that these viral proteins are highly immunogenic in nature. We have also analyzed the serum of nine healthy people living in West Africa who were infected with HTLV-IV, a closely related retrovirus. Nine of nine seropositive people had antibodies that cross-reacted to p34 of HTLV-III/LAV, whereas only seven of nine reacted to p64/p53. These studies and our earlier observations indicate that current diagnostic procedures for screening for HTLV-III/LAV infection may also detect HTLV-IV seropositive individuals, pointing to a need for more specific assay systems.

The human T-lymphotropic virus type III (HTLV-III) is the primary cause of the acquired immunodeficiency syndrome (AIDS) and related disorders (ARC). Prior studies have reported that nearly all symptomatic patients with AIDS or ARC manifest antibody to HTLV-III. This observation has engendered efforts to screen for HTLV-III, especially prior to blood donation, with assays for antibody to HTLV-III. We report the first two cases, one with AIDS and one with ARC, that are HTLV-III virus positive but antibody negative. Accurate diagnosis of HTLV-III infection in some cases may require direct virus culture or tests for antigen. In addition, lack of HTLV-III antibody may indicate an atypical clinical course of AIDS.