[Antibodies against Trypanosoma cruzi in intact mice and their oncoprotective effect].

Trypanosoma cruzi antibodies that are important in the anticancer effect of this species of Trypanosoma were first detected in 14% of the 374 examined intact mice. These background antibodies were polyclonal, i.e. they reacted with one or other of 9 genetically different T. cruzi clones and detected antigenic determinants in different structures of a Trypanosoma cell. Their spread in the population varied with animal batches; the titers were not greater than 1:40 and the level remained steady during a one-month observation. The growth of Ehrlich's adenomacarcinoma inoculated to these mice was inhibited by 1.5-2.5 times and, in some cases, terminated in total regression. The paper discusses the capacities of such antibodies in man and their inductor-commonness of the antigens of the normal intestinal microflora and the cells of the vertebrate with T. cruzi.

In vivo anticancer activity of lysates from trypanosoma cruzi of different genetic groups.

Lyzed epimastigotes of Trypanosoma cruzi clones P209-1, Gamba1, Sp104-1, MASu, Y7/1, MN12, Cl-Brener, 86/2036, Y7/2-1 inhibit the growth of Ehrlich adenocarcinoma in mice. the tumor decreased 1.5-3 times after 12 daily injections of lysates from 15 million epimastigotes. The protective effect progressed after the injections were discontinued and depended on the dose and lysate producer clone. Trypanosoma lysates in the studied doses were nontoxic.

[Immunization against Trypanosoma cruzi and tumor growth in mice].

The evidence has been produced that immunological mechanisms are involved in the known anticancer phenomenon of T. cruzi. Non-inbred albino mice were immunized with avirulent cultures of three strains and seven clones and then transplanted a tumor--sarcoma-180 or Ehrlich's adenocarcinoma. The used cultures induced the generation of T. cruzi antibodies whose level peaked by postimmunization days 50-60: the titers being 1:40-1:80 and the spread among the mice being 60%. Concurrently, immunization against T. cruzi provided a certain oncoprotective effect. In the immunized mice, the sizes of sarcoma-180 and adenocarcinoma were 1.5-2.0 and 2.0-2.5 times, respectively, less than those in the non-immunized ones. The antitumor protection was directly related to the murine blood T. cruzi antibody level during which implantation of a tumor occurred. At the peak of an immune response, the effect was 2 times higher than that in the early postimmunization periods. T. cruzi strains that were more immunogenic than clones ensured a more significant oncoprotection. The latter was more considerable in mice having antibody titers of 1:40-1:80 than in those with antibody titers of 1:10-1:20 and particularly in the animals showing no humoral response to the administration of the parasites at all.

Genetic heterogeneity of Trypanosoma cruzi and its direct anticancer effect in cultured human tumor cells.

The direct inhibitory effect of Trypanosoma cruzi epimastigote lysates on in vitro cultured human breast cancer MCF-7 cells differs in various genetic groups and cloned subgroups of Trypanosoma.

[Anticancer properties of flagellate protozoan Trypanosoma cruzi Chagas, 1909]. / Protivorakovye potentsii zhgutikovogo prosteishego Trypanosoma cruzi Chagas, 1909.

The anticancer activity of Trypanosoma cruzi has been confirmed by the example of seven strains. Five virulent strains induced the infection, which inhibited sarcoma-180 growth 1.5-22.0 times. The parasites featured tumortropism; i.e., the successfully developed in cancer cells and even preferred them to normal cells. This taxis-based phenomenon was particularly pronounced at cocultivation of the normal and cancer cells. Cultures of the seven (avirulent and virulent) strains can produce an anticancer agent that selectively damages human cancer cells in vitro. The long-term anticancer effect of T. cruzi or preparations from it, as well as possible its cancer preventing effect, has been demonstrated. Three problems are discussed on the basis of the obtained and recently published data: (1) the mechanism of T. cruzi anticancer effect; (2) the nature of the anticancer agent; and (3) the distribution of the considered phenomenon among trypanosomatides. The anticancer activity of T. cruzi may be due to a combination of surface cellular antigens and an inhibiting or lysing factor.

[The virulence, metacyclogenesis and respiratory enzymes of Leishmania isolated in culture from laboratory animals]. / Virulentnost', metatsiklogenez i dykhatel'nye fermenty leishmanii, vydelennykh v kul'turu ot laboratornykh zhivotnykh.

It has been shown that an increase of virulence of Leishmania major, L. tropica, L. braziliensis as a result of passing through animals and its decrease during the cultivation are accompanied by certain changes of biochemical characteristics of these promastigotes. In the former case the activity of NADP-H-diaphorase and peroxidase of promastigotes and their ability to be transformed into final (invasional) metacyclic forms increase and in the latter case these characteristics decrease. The level and duration of virulence in culture depend not only on absolute value of the above-mentioned characteristics but also on the graduality of their change. Metacyclogenesis and activity of oxidative enzymes are suggested to be the correlates of virulence of various Leishmania species.

[The virulence and cytochemical properties of Leishmania major during long-term cultivation]. / Virulentnost' i nekotorye tsitokhimicheskie kharakteristiki Leishmania major v protsesse dlitel'nogo kul'tivirovaniia.

It has been shown that morphogenesis of Leishmania major in each culture passage is characterised by the depletion of RNA and increase in its dispersion degree, by the change of the NADP-H-diaphorese, peroxidase and Janus green-B-oxidative activity in the promastigotes. Cytochemical peculiarities of invasive metacyclic promastigotes are an extreme depletion of RNA, its disperse form, a low activity of oxidative enzymes. This properties may manifest the pre-adaptation of Leishmania promastigotes to the development in vertebrate host. In the process of long-term cultivation of L. major the virulence, the metacyclogenesis, and the level of NADF-H-diaphorase and peroxidase activity decrease from passage to passage, but the ability to oxidate the Janus green-B increases.

[The forms of the intercellular contacts of Leishmania in culture]. / O formakh mezhkletochnykh kontaktov leishmanii v kul'ture.

Two kinds of intercellular interactions have been observed in cultures of 12 investigated Leishmania species (L. major, L. tropica, L. donovani, L. infantum, L. sp. ZMA, L. mexicana, L. hertigi, L. braziliensis, L. tarentolae, L. adleri, L. gymnodactyli, L. gulickae). The first kind looks as adhesion of two specimens with their fore-ends. This way is characteristic of promastigotes of different morphotypes as well as of the interphase and dividing organisms to be most frequently seen in L. mexicana and L. gymnodactyli, and in both dark and lucid forms. The second kind of intercellular interactions involves a coupled adhesion of morphologically similar promastigotes with free ends of flagella. It is most characteristic of L. gymnodactyli and specially of dark promastigotes. Proves are provided that both the kinds of cell interactions are not associated with cell division, that they may only partially be connected with the phenomenon of rosette formation, and that they represent different phenomena. It is supposed that the intercellular contacts with the fore-ends may reflect gene exchanges in two partners, with a possible involvement of the kinetoplast DNA.

[Differentiation of Leishmania in culture]. / Differentsirovka leishmanii v kul'ture.

During their cultivation on diphasic medium Leishmania donovani, L. major and L. gymnodactyli pass through the regular differentiation within the promastigote stage of the life cycle that involves a gradual change of the four main morphological forms: 1) extremely basophilic, short, wide, actively dividing cells; 2) lightening longer forms with pointed posterior ends; 3) long, cigar-shaped uniformly light specimens with the clear nucleus in the central or posterior position and distinct karyosome; 4) small narrow nearly non-basophilic cells with a long compact nucleus and a rather large kinetoplast. The latter are similar, on the one hand, to the final stage of Leishmania development in Phlebotomus and, on the other hand, to metacyclic forms of Trypanosoma cruzi infective for the vertebrate host.

[Polymorphism of Trypanosoma cruzi in the blood of a vertebrate host]. / Polimorfizm Trypanosoma cruzi v krovi pozvonochnogo khoziaina.

Tetramorphism of trypomastigote forms has been discovered in the blood stream of mice infected with Trypanosoma cruzi, that is C slender, C middle, S slender, S middle and forms intermediate between C and S. Regular changes of forms have been observed in the course of the infection. In the middle of the process, at the moment of maximum destruction of parasites affected by immunosystems of the host, C-forms prevailing on the whole substantially give place to S-forms, slender variants being replaced by middle ones within each of them. Polymorphism in the bloodstream of the vertebrate host is the general property of all trypanosomes, with their common biological value: immunological adaptation to parasitism in the blood and preadaptation to the continuation of the life cycle in the invertebrate host.

[Cytochemical study of free-living flagellates of suborder Bodonina. I. Morphology and nucleic acids]. / Tsitokhimicheskoe issledovanie svobodnozhivushchikh zhgutikovykh podotriada Bodonina. I. Morfologiia i nukleinovnye kisloty.

Nucleic acids (DNA and RNA) have been discovered in the kinetoplast of free-living Bodonina: Bodo caudatus, Pleuromonas jaculans, Rhynchomonas nasuta--by means of cytochemical methods. The kinetoplast has variable contents of nucleic acids whose chemoarchitectonics is due to their non-homogeneous distribution within the kinetoplast. The Feulgen reaction in the kinetoplast is more intensive than in the nucleus. Kinetoplast is closely connected with the cytoplasmic RNA metabolism. Many individuals of R. nasuta were found to have two kinetoplasts, no other signs of cell division being observed. P. jaculans has up to 45% of dyskinetoplastic forms.