Abstract: An immunomodulatory peptide is disclosed which is a thymic humoral factor .gamma.2 (THF-.gamma.2) analog of at least eight amino acids or a functional derivative or a salt thereof. The peptide has the amino acid sequence: Leu-Glu-Asp-Gly-Pro-Lys-Phe-Leu (SEQ ID No:1) but differing therefrom by(i) addition of one to three amino acids at the N- and/or C-terminus;(ii) substitution of one to four amino acids by a protein natural or non-natural amino acid;(iii) cyclization through a free carboxyl group and a free amino group or through disulfide bonds of cysteines residues; or(iv) linkage of two to four sequences of modified sequences of (I) corresponding to anyone of (i), (ii), or (iii) above, through a peptidic or non-peptidic linkage.

Abstract: The invention relates to analogs of thymic humoral factor .gamma.2 (THF-.gamma.2) having at least 4 amino acid residues and corresponding to the sequence of THF-.gamma.2 of the formula I:Leu-Glu-Asp-Gly-Pro-Lys-Phe-Leu Ibut differing therefrom by addition, deletion or substitution of one or more amino acid residues, or by cyclization, or by linkage of two or more sequences (I) or modified sequences (I) either directly or through a peptidic or non-peptidic chain.The THF-.gamma.2 analogs of the invention and the functional derivatives and salts thereof are for use as immunomodulatory in pharmaceutical compositions.

Abstract: Novel peptide materials having thymic humoral activity are disclosed having the respective amino acid sequences of:Leu-Glu-Asp-Gly-Pro-Lys-Phe-Leu;His-Pro-Leu-Pro-Asp-Leu-Tyr; andPhe-Val-LeuThese novel peptides can be isolated from natural thymus glands or can be prepared synthetically.

Abstract: Chemically substantially pure and uniform THF (thymic hormone), substantially devoid of endotoxins, having a molecular weight of 3323.sup..+-. 220, an isoelectric point of from 5.7 to 5.