Antibody to p40tax protein of human T cell leukemia virus 1 and infectivity.

To investigate the physiologic significance of antibody to human T cell leukemia virus type 1 (HTLV-1) tax gene product (p40tax), 147 male and 243 female HTLV-1 carriers were examined for anti-p40tax, and 104 carriers were checked for anti-p40tax an average of 5.4 times during an 8-year period. Prevalence of anti-p40tax was significantly higher in female (62.6%) than in male subjects (51.0%; P less than .05). Anti-p40tax status did not change in most during the observation period. There were significantly more HTLV-1 carriers among children of anti-p40tax-positive mothers (45.3%) than among those from anti-p40tax-negative mothers (20.0%; P less than .01). However, no significant difference was observed between wives of p40tax-positive and -negative men. The p40tax antibody may be a marker of relative infectivity of HTLV-1, albeit an imperfect one.