Association with T. vaginalis Soszka and Kuczyńska described the appearance of morphological variations of Lactobacilli, when grown in the presence of a high concentration of Trichomonas vaginalis. The authors interpreted the observed atypical (coccoid) cell morphology as an involution (senescent, dying) form. Goisis et al. have shown, that shortened and coccoidal lactobacilli are not only present in the primary secretion samples of trichomoniasis patients, but also in the cultures started from these samples, free from competitive microorganisms and under optimal culture conditions, suggesting that the coccoid bacteria may represent a distinct viable phenotype. Contrastingly, the isolates from vaccinated patients tended to assume bacilliform also in culture. The general consensus remains, that at least some of the morphology variants seen under trichomoniasis versus health are to be interpreted as representations of "true commensal" versus more pathogenic strains (genotypes), although a possible relationship between morphotype and distinct environment-driven proteome profiles has not been excluded. Immunological cross-reaction with T. vaginalis The antigenic material responsible for the effect of lactobacillus vaccines is most likely surface antigens of the aberrant lactobacilli. The anti-trichomonal effect of SolcoTrichovac has led multiple researchers to investigate the possibility of shared surface antigens between the specific strains used in the vaccine and T. vaginalis. The theory of antigenic cross-reactivity was put to the test by Stojković. Indirect immunofluorescence was performed on trichomonads treated with rabbit antisera against aberrant lactobacilli and against T. vaginalis. Specific immunofluorescence was observed on those protozoa which had been treated with anti-lactobacillus serum and anti-trichomonas serum, but not on those treated with serum from non-vaccinated animals. Bonilla-Musoles performed an electron microscopic study on trichomonads treated with serum from women who were previously vaccinated with SolcoTrichovac. After three days the trichomonads exposed to antibody-containing serum showed marked signs of destruction, similar to those observed under the influence of metronidazole. The electron micrographs revealed cytoplasmic swelling, dilation of the reticuloendothelial lamellae and formation of vacuoles as well as evaginations and invaginations of cellular membranes. Alderete, Gombošová and others however described contrary findings, and attributed any anti-trichomonal activity of lactobacillus vaccines to non-specific immune mechanisms. The question of immunological relationship between aberrant lactobacilli and T. vaginalis has not been answered conclusively. Phylogenetic relationships to T. vaginalis An intriguing hypothesis was advanced by Alain de Weck that suggests horizontal gene transfer between specific aberrant strains of Lactobacilli used in SolcoTrichovac and T. vaginalis, which leads to their (possible) cross-immunogenicity. Phylogenetic