Conjugated peptides include a first peptide component which is an antigen associated with autoimmune disease, allergy, asthma or transplantation rejection and binds to an antigen-specific receptor on a T cell, and a second peptide component which corresponds to an "antigen presenting molecule", namely, a peptide binding to a T cell surface receptor, which would normally promote T cell activation when the first peptide is bound to its antigen-specific T cell receptor. However, in this invention, the second peptide component has an amino acid sequence which is a modification of an antigen presenting T cell binding peptide, such modification blocking or inhibiting the engagement of receptor sites on the T cell surface (other than the antigen-specific T cell receptor). As a result, T cell activation is prevented, and is directed through antigen-specific T cell receptor occupation, without T cell activation, leading to antigen-specific T cell anergy and cell death. Administration of the conjugated peptide to an animal will provide protection against disease associated with the first peptide component, resulting from the elimination of the T cells bearing the antigen-specific receptors for that anti genic peptide. The conjugated peptides of this invention provide antigen-specific protection without impairing the immune response to other antigens.