Specific immune responses to skin test antigens following repeated multiple antigen skin tests in normal individuals.

Delayed type hypersensitivity (DTH) responses are used widely to evaluate immunologi-cal competence, even though there is a paucity of information about serum antibody (Ab) responses also induced by DTH test antigens and procedures. In a prospective controlled study of 24 healthy adult volunteers, antigen (Ag) specific DTH and serum Ab responses induced after two skin tests (4 weeks apart), each using the same seven test antigens, were concurrently measured over an 8 week course. Standardized preparations of proteus, tuberculin, Candida and tetanus antigens used in each of the multiple antigen skin tests to evaluate DTH responses were used also in solid phase bead-type radioimmunoassays (SBRIA) to measure levels of Ig specific, Ag specific Ab in serum specimens collected serially from the volunteers. In addition, DTH responses of each volunteer to diphtheria, streptococcus and trichophyton antigens were assessed in each skin test, while levels of serum Ab to , measles virus and KLH were measured by SBRIA. A significant correlation of DTH responses with Ab levels after the initial skin test was observed only for one Ag, i.e., decreased DTH and increased IgG Ab responses to tetanus. Transitory significant changes in levels of Ig specific antibody to six of the seven antigens were detected by SBRIA. Following the second skin test, DTH reponses to tetanus and streptococcus, but not the other five skin test antigens, were significantly decreased, while no significant effects on antibody levels to SBRIA tests Ags were observed. Results of this study indicate that no long term DTH or Ab responses to skin test antigens were stimulated in normal adult individuals after repeating multiple antigen skin tests.