Suppression of contact sensitivity by IgG1 antihapten antibody in contact-sensitized guinea pigs.

The guinea pig sera obtained 2 weeks after 1-fluoro-2,4-dinitrobenzene sensitization had ability to suppress elicitation of contact sensitivity when transferred intravenously into contact sensitized guinea pigs. The activity was found only in the sera obtained 2 weeks after the sensitization, whereas the sera obtained 1 and 3 weeks after the sensitization had no effect on contact sensitivity. Pretreatment of cyclophosphamide abolished the generation of the suppressive factor. The suppressive factor was hapten-specific. It was eluted from a Sephadex G-150 column into 7S gamma-globulin fraction and from DEAE ion exchange cellulose column into IgG1 fraction. The suppressive activity was absorbed on a dinitrophenylated bovine gamma globulin Sepharose 4B column and was eluted by either acidic buffered solution or dinitrophenol from the affinity column. It was absorbed by antiguinea pig IgG1-Sepharose and not by antiguinea pig IgG2-Sepharose, Therefore, the suppressive activity found in the sera of 1-fluoro-2, 4-dinitrobenzene sensitized guinea pigs was attributed to IgG1 antihapten antibody.