In vitro immunogenicity of trinitrophenylated bacteriophage T4. I. Lack of helper cell cooperation

A primary immune response was obtained in vitro to trinitrophenylated bacteriophate T4 (TNP-T4) by using normal BALB/c spleen cells challenged in vitro. The primary response was limited to anti-TNP; we failed to find evidence of a primary anti-T4 response in spleen cell cultures challenged with either TNP-T4 or native T4. In vivo priming with the carrier T4 failed to enhance the subsequent in vitro response to TNP-T4 although such priming sometimes caused suppression of the anti-hapten response. The addition of excess free carrier to spleen cell cultures challenged with TNP-T4 failed to suppress the anti-tnp response. Spleen cells treated with anti-theta plus complement were unaffected in their ability to respond to TNP-T4. We conclude that TNP-T4 should be classified among the thymus independent antigens.