Abstract: Polypeptide useful for the preparation of antimalarial vaccines and of diagnostic kits for the detection of antisporozoite antibodies in clinical samples of malariated persons, constituted by: a synthetic peptide, which repeates the region I of P. falciparum and by a variable number of repetitive tetrapeptide units of CS protein of P. falciparum linked to each other by an amidic bond between the tail proline of I region and the head asparagine of the first tetrapeptide.

Abstract: Synthetic polypeptides constituted by at least two consecutive repeating units of (Asn-Asn-Pro) sequence are powerful immunogens in test animals.The formed antibodies recognize both the synthetic polypeptides and the immuno-dominant epitope of the circumsporozoitic protein of Plasmodium falciparum.Said polypeptides, which can be obtained in pure form, are particularly useful for the preparation of antimalarial vaccines and of diagnostic kits for the determination of malarial affections.

Abstract: Immunologically active polypeptide composition constituted by polypeptides having the formula:H--(Glu--Glu--Asn--Val--Glu--His--Asp--Ala).sub.n --OHwherein Glu=Glutamic Acid;Asn=Asparagine;Val=Valine;His=Histidine;Asp=Aspartic Acid;Ala=Alanineand wherein n has a value equal to, or larger than, 2.Said composition is useful for the preparation of antimalarial vaccines and of diagnostic kits for the detection of antimerozoite antibodies.

Abstract: Synthetic peptides constituted by at least two repeating, consecutive units of asparaginyl-proline (Asn-Pro).sub.n sequence, are described.The peptides are powerful immunogens, capable of inducing in laboratory animals the formation of a high concentration of antibodies capable of reacting both with the (Asn-Pro).sub.n peptides, and with the immunodominant epitope of the circumsporozoite protein of Plasmodium falciparum.The peptides, which can be obtained in a pure form by chemical synthesis, are particularly useful for preparing antimalarial vaccines and diagnostic kits for the determination of malaria in man.

Abstract: Synthetic peptides consisting of at least two consecutive repeating units of the sequence (Ala-Asn-Asn-Pro) are powerful immunogens in experimental animals.The antibodies which form recognize both said synthetic peptides and the immunodominant epitope of the circumsporozoitic peptide of Plasmodium falciparum.Said peptides, obtainable in pure form, are particularly useful for preparing antimalarial vaccines and diagnostic kits for the determination of malarial affections.

Abstract: Immunologically active polypeptides constituted, towards the N-terminated end, by an Asn-Val-Asp-Pro-Asn-Ala-Asn-Pro sequence repeated three times and, towards the C-terminated end, by at least three quadruplets with an Asn-Ala-Asn-Pro sequence, linked with each other by means of an amidic bond between the end proline of the first sequence, and the initial asparagine of the first quadruplet.Said polypeptides reproduce nearly exactly the sequential structure of the circumsporozoite protein of P. falciparum, and are useful for the preparation of antimalarial vaccines and of diagnostic kits for the detection of antisporozoite antibodies in clinical samples of malariated persons.

Abstract: New partially retro-inverted tuftsin analogues of general formula I ##STR1## wherein R represents the side-chain of the amino acids threonine, methionine or leucineR.sup.1 represents the side-chain of the amino acids lysine or arginineR.sup.2 is hydrogen or a metabolically labile acyl group,all the asymmetric carbon atoms are either of the S- or R-configuration, or, alternatively, the first, third, and fourth asymmetric carbons, starting from the N-terminal residue, are of the S-configuration while the second one is of the R- or (R,S)-configuration, and the corresponding pharmacologically acceptable salts, esters and amides. The new compounds which share the same pharmacological properties of tuftsin, are much more stable toward the enzymatic degradation than the parent molecule.

Abstract: Hexapeptides with vasodilating and hypotensive activity are described corresponding to the formula: ##STR1## wherein:X is a hydrogen atom or an acyl radical R.sub.3 -CO- wherein R.sub.3 is a straight or branched (C.sub.1 -C.sub.7)alkyl group,R.sub.1 and R.sub.2, each independently, represent the side-chain residue of the amino acid glycine (--H), alanine (--CH.sub.3), valine ##STR2## leucine ##STR3## or isoleucine ##STR4## Arg is the abbreviated designation for arginine, Pro is the abbreviated designation for proline, Tyr is the abbreviated designation for tyrosine, and the pharmaceutically acceptable salts, lower alkyl esters and amides thereof, a process for their preparation and the pharmaceutical compositions containing them.

Abstract: Pharmacologically active, partially retro-inverso, neurotensin-like peptides lasting longer than the natural hormone, corresponding to the formula ##STR1## wherein R.sup.1 and R.sup.2 are straight or branched (C.sub.1 -C.sub.7) alkyl radicals.The new compounds are useful as vasodilating and hypotensive agents.