[The forms of the intercellular contacts of Leishmania in culture]

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.