Synthesis and immunomodulatory activity of [60]fullerene-tuftsin conjugates.

Immunomodulating peptide tuftsin (Thr-Lys-Pro-Arg) was covalently conjugated to fullerene C(60) by two different ways to prepare NH(2)-tuftsin-C(60) and C(60)-tuftsin-COOH. The two new compounds were intensively characterized. The synthetic C(60)-tuftsin conjugates were assayed for their stability against leucine aminopeptidase degradation. And the immunostimulating activities to murine peritoneal macrophages were investigated in vitro. Compared with the natural tuftsin, significant enhancement of phagocytosis, chemotaxis activities and major histocompatibility complex class II (MHC II) molecule expression were observed in macrophages stimulated by both of the conjugates. The two conjugates also exhibit complete resistance to enzymatic hydrolysis, and they are non-toxic to macrophages in the tested concentrations. On all accounts, these results suggest that the C(60)-tuftsin conjugates can be used as potential candidates of immunomodulators and vaccine adjuvants.

Effect of tuftsin on embryo vaccination with Newcastle disease virus vaccine.

The effect of tuftsin of embryo and post-hatch vaccination with NDV-F was studied. The embryo vaccination with NDV-F resulted in more number of dead-in-shell embryos. To overcome this problem, the vaccine was treated separately with ethyl methane sulfate (EMS) and 5-fluorouracil (5-FU) and administered. Treating the vaccine with 5-FU resulted in better hatchability as compared to EMS treatment. In embryo, NDV antibody titres increased upto 2 weeks of age and declined thereafter, whereas in post-hatch vaccination, the antibody titre increased from second to fourth week of age and declined thereafter. The seroconversion was better when the vaccine was given along with tuftsin either to embryos or chicks (post-hatch vaccination) as compared to those vaccinated without tuftsin. Moreover, the percentage of hatchability was more in tuftsin administered groups. It was found that embryo vaccination can ensure definite protection during the early life of the chicks despite the presence of maternal antibodies. In cases where breeder vaccinations do not result in concomitant transfer of antibody to progeny chicks, embryo vaccination would give only neonatal resistance. During the later stages, embryo vaccination did not confer any advantage over post-hatch vaccination.

Tuftsin-AZT conjugate: potential macrophage targeting for AIDS therapy.

The IgG-derived immunomodulating peptide tuftsin, Thr-Lys-Pro-Arg, is recognized by specific receptors on phagocytic cells, notably macrophages, and is capable of targeting proteins and peptides to these sites. Aiming to target 3'-azido-3'-deoxythymidine (AZT) to HIV-infected macrophages, a conjugate of AZT with tuftsin was synthesized. The AZT-tuftsin chimera possesses the characteristic capacities of its two components. Thus, like AZT, it inhibits reverse transcriptase activity and HIV-antigen expression, and similarly to tuftsin, it stimulates IL-1 release from mouse macrophages and augments the immunogenic function of the cells. Importantly, the conjugate is not cytotoxic to T-cells. The results suggest that the AZT-tuftsin conjugate might have potential use in AIDS therapy.

Further investigations on the antinociceptive activity of tuftsin analogs.

C-Terminal dipeptide fragment of tuftsin, Pro-Arg, substituted by D-amino acids, and tuftsin analogs with n-hexyl- and n-heptylamine coupled to their C-termini were synthesized by a classical method in solution and their antinociceptive activity was measured by tail flick immersion test (0.4 microM/icv). D-Pro-D-Arg and D-Pro-L-Arg showed an analgesic activity, with the duration of 60 and 40 min, respectively. The strong behavioral effects observed after injection of D-Pro-D-Arg were decreased by naloxone. L-Pro-D-Arg and Thr-Lys-Pro-Arg-HxA display no antinociceptive effect; the tetrapeptide amide showed some toxicity effects. Thr-Lys-Pro-Arg-HpA was very toxic and caused death of all experimental animals. This effect was not influenced by previous injection of naloxone.