Pharmaceutical composition (A), particularly a vaccine, containing a peptide hybrid (PH) analogous to a parent peptide or protein (PP) but including at least one aza-beta 3-aminoacyl residue (X), optionally also a vehicle, is new. Pharmaceutical composition (A), particularly a vaccine, contains a peptide hybrid (PH) analogous to a parent peptide or protein (PP) but including at least one aza-beta 3-aminoacyl residue (X), optionally also a vehicle. (X) has the structure RNH-NR 1-CH 2-CO-； -NH-NR 1-COOH or -NH-NR 1-CO- when present at the N-terminus, C-terminus or internally. R : hydrogen or amino protecting group for amino acids, e.g. Fmoc (fluorenylmethoxycarbonyl), Boc (tert-butoxycarbonyl) or Z (benzyloxycarbonyl)； R 1amino acid sidechain. Independent claims are also included for: (1) PH containing at least one (X) and at least one amino acid (aa) from PP, as new compounds； (2) poly- or mono-clonal antibodies (Ab) directed against PH； (3) anti-idiotypic antibodies (AAb) able to form a complex with Ab； (4) complex (C1) between PH and a component of the major histocompatibility complex, optionally also a T-cell receptor (TCR)； (5) complex (C2) between PH and TCR； (6) in vitro diagnosis of diseases associated with presence of an exogenous or endogenous protein, using PH to detect specific antibodies or Ab to detect the protein； (7) kit for method (6)； (8) preparing aza-beta 3-amino acids (Y)； and (9) Fmoc-aza-beta 3-(Gly, Lys, Asp, Met, Arg and Tyr) as new compounds. ACTIVITY : Dermatological； Immunosuppressive； Antiinflammatory. No biological data given. MECHANISM OF ACTION : Vaccine； induction of antibodies and cellular (cytotoxic or auxiliary) responses. Balb/c mice were immunized with the 88-99 epitope of histone H4 (parent peptide), then ( in vitro) T lymphocytes from the mice restimulated and cell proliferation determined from incorporation of tritiated thymidine. The index of stimulation, at 90 MicroM, was about 7 for restimulation with the parent peptide and
