Abstract: Methods for isolating novel antigens that stimulate CD4-positive T cells are disclosed. The methods provided comprise the steps of: transforming a host cell with a plasmid suspected of containing such a DNA sequence encoding such an antigen and inducing antigen expression; incubating the transformed host cell with at least one dendritic cell for a period of time sufficient to form a peptide/MHC Class II complex on the dendritic cell, the peptide being derived from the expressed antigen; incubating the dendritic cell with CD4+ T cells; determining the level of CD4+ T cell stimulation, thereby identifying a transformed host cell that expresses at least one CD4+ T cell-stimulating antigen; and isolating DNA from the transformed host cell. DNA sequences isolated using such methods, together with antigens encoded by such DNA sequences, are also provided.