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Biomedical subjects

O Procházka

Publications and source records attributed to O Procházka.

At least 19 recordsLinked to original sources

Complex surveillance of streptococcus pyogenes. VI. Relationship between hypersensitivity to zymosan and indicators of immunity against group A streptococci.

A prospective study involving 20 volunteers was designed to test relationships between the sensitivity to zymosan and the indicators of nonspecific immunity against streptococci (inhibitory activity of blood and production of mediators). The immunization with Mannozym produced a conversion of zymosan-induced MIF with a subsequent improvement of immunity indicators in 4 out of 7 primovaccinated and 2 revaccinated subjects. This effect was detectable in some vaccines within 2-4 days after immunization and persisted for up to 5 months. Initially detected changes, their kinetics in the vaccinated subjects as well as time-related variations in the pattern of indicators during a one-year period of observation seem to suggest that there was a relationship between the natural and induced cellular sensitivity to zymosan and the inhibitory activity of blood. The inhibitory activity of blood was effectuated through enhanced mediator-induced phagocytic activity and nonspecific opsonin mechanisms. The mediators fluctuated in their values with time and were demonstrable in immunized subjects. There were observed interlinked reactions of cellular immunity with zymosan, peptidoglycan and streptococci. The mechanisms found are believed to constitute a fundamental, relatively easy-to-stimulate means of human immunity which may explain the experimental and epidemiological inconsistencies in the strictly type-specific interpretation of the M - anti-M system. Under in vitro conditions the effect of nonspecific immunization was bacteriostatic, but the role of these nonspecific mechanisms under conditions in vivo remains unclear. It is recommended that effectiveness of nonspecific immunization be verified under conditions of natural infection in man.

Blood Bactericidal Activity↗

Complex surveillance of Streptococcus pyogenes V. Protective features complex surveillance of streptococcus of cell-mediated immunity against group a streptococci.

Exoproducts of incubated white blood elements from persons hypersensitive to zymosan were found to promote the phagocytic activity of human microphages (and guinea pig macrophages) under conditions of a combined model of "MIF-opsonophagocytic test". The stimulation resulted in a bacteriostatic effect, was non-type-specific and improved microphage potential to inactivate streptococci opsonized with anti-M antibodies in low titre. The microphages pre-exposed to anti-M sera remained unaffected, the effect was non-species-specific and nontype-specific and the stimulation resulted from the action of albumin fraction exoproducts. This seems to suggest that human mediators (lymphokines) may promote the activity of phagocytes. The cell-mediated immunity appears thus to have protective features even in the case of streptococci which are the typical extracellular parasites. The drawbacks of the model used, which make it difficult to quantify the found mechanism under in vivo conditions, are discussed in detail.

Animals↗

Complex surveillance of Streptococcus pyogenes. IV. The phenomenon of interference of human serum under the conditions of the bactericidal test.

The phenomenon of interference of human sera under the conditions of the bactericidal test was described. In the presence of these sera, secondarily non-resistant strains of Streptococcus pyogenes were capable of vigorous growth and anti M 12 bactericidal activity was impaired. The factor was found in the albumin fraction and has probably the character of a blocking cytophilic lymphokin. It can markedly distort the interpretation of the bactericidal test.

Adult↗

Complex surveillance of Streptococcus pyogenes. II. Resistance in human blood and bactericidal activity receptors of field and collection streptococci.

A comparative study of a series of 31 epidemic streptococci and 36 collection M protein producers showed no statistically significant difference in their resistance in human blood. Even highly resistant field strains did not produce M protein (as the main bactericidal activity receptor) under laboratory conditions, however, although under natural conditions they left an anti-M response in the exposed population. Streptococcal resistance is not generally associated with M protein, but is influenced by another factor.

Antibodies, Bacterial↗