The lymphokine secretion patterns of seven independent 91-101.lambda 2(315)/I-Ed specific, CD4+ T-cell clones have been investigated. Six of the clones are of the Th1 type as they secrete IL2 and IFN gamma, but not IL4. Some of these six Th1 clones produce TNF alpha/beta, and some produce minor amounts of IL5 and IL6. One clone is of the Th2 type as it produces IL4, IL5, and large amounts of IL6, but not IL2, IFN gamma or TNF. The Th1/Th2 classification does not have any stringent relationship to immunization protocol, fine specificity and V alpha/V beta gene segment utilization. The immunoregulatory significance of our findings for Id/MHC-dependent T-B cell interaction is discussed.