Section 16 — Human Cytogenetics 



human heteroploid cell strain which exhibit 

 marked variations in alkaline phosphatase 

 activity. The karyotypes of the deficient lines 

 showed a loss of a number of chromosomes. 

 The detailed morphological analyses of chromo- 

 somes, made it possible to individuate the 

 missing chromosomes, thus indicating the possible 

 site of genetic control of the character. 



occur, but in acute myeloid leukaemogenesis 

 permanent derepression occurs, with subsequent 

 mutation affecting the reactive site and occa- 

 sionally mutation affecting other points in the 

 enzyme protein molecule. These phenomena 

 have important bearing on gene regulation in 

 mammalian cells, and on aberrations of gene 

 control in carcinogenesis. 



16.40. Genetic and Biochemical Studies on Mutant 

 Cell Lines in Culture. Robert S. Krooth 

 (Ann Arbor, U.S.A.). 



Galactosemia in man is a rare recessive disease. 

 Cell lines developed from the tissue of patients 

 with galactosemia and from the tissues of normal 

 controls have been studied after prolonged 

 growth in vitro. When a suitably constituted me- 

 dium is employed, the galactosemic cells appear 

 to be unable to grow in galactose, whereas the 

 normal cells can. The cultured galactosemic cells 

 do not oxidize galactose-1-C 14 to C 140 2 in 

 short term experiments while cultured cells 

 from control patients perform the reaction readi- 

 ly. These two properties of galactosemic cells 

 have thus far proven to be a stable phenotype of 

 the line. Analogous experiments have also been 

 performed on cell lines derived from patients 

 with another recessve abnormality — acatalasia. 

 Here too the characteristic biochemical abnor- 

 mality appears to persist in the cultured cells. 

 Preliminary genetic experiments on these lines 

 will be described, and the results of a further 

 search for biochemical markers in cell cultures 

 will be summarized. 



16.42. Mitotic and Immune Response of Human 

 Peripheral Lymphocytes in vitro. N. Hashem 

 (New York, U.S.A.). 



During the investigation of the mechanism of 

 the mitogenic action of phytohemagglutinin on 

 human peripheral blood lymphocytes, it was 

 noted that mitotic activity is associated with 

 leucocyte agglutination, gammaglobulin pro- 

 duction by the lymphocytes and morphological 

 changes of the cells during culture. This im- 

 mune-like response prompted investigation of 

 the action of specific antigens on lymphocytes 

 from individuals sensitized to the antigens. 

 With the use of tuberculin purified protein deriv- 

 ative and pertussis vaccine it was demonstrated 

 that mitotic activity resulted in cultures of 

 peripheral lymphocytes from sensitized indi- 

 viduals. It was also noted that morphological 

 alterations and gammaglobulin production was 

 limited to only a group of the cells in culture. 

 These experiments have demonstrated the po- 

 tential ability of "clones" of peripheral lym- 

 phocytes to respond to specific antigens with 

 gammaglobulin production and mitotic activity. 



16.41. Leucocyte Enzyme Induction and Repression 

 and Human Leukaemogenesis. Chev. Kidson 

 (London, Great Britain). 



Under certain conditions two catalases, a 

 and b, may occur in human leucocytes of the 

 myeloid type. Catalase a is always present in 

 all leucocytes; catalase b, having a different 

 pH optimum, occurs intermittently in normal 

 myeloid cells, never in lymphoid or erythroid 

 cells. In acute myeloid leukaemia catalase b is 

 always present, but with altered reactive site, and 

 occasionally altered electrophoretic mobility. 

 Catalase b is not induced in normal myeloid 

 cells during m vitro phagocytosis, nor by 

 anacrobiosis. It appears that catalase b induc- 

 tion in normal human myeloid leucocytes is 

 due to reversible derepression: in the normal 

 cells repression of catalase b synthesis can readily 



16.43. Variation of In Vitro Gamma Globulin Pro- 

 duction by Human Lymphocytes. Fritz Bach 

 and Kurt Hirschhorn (New York. U.S.A.). 



Human lymphocytes, obtained from heparini- 

 zed peripheral blood by sedimentation and sub- 

 sequent removal of polymorphonuclear leuko- 

 cytes, were grown in tissue culture. In the pres- 

 ence of phytohaemagglutinin and other sub- 

 stances, all lymphocytes have the potential to 

 produce gamma globulin. This problem was 

 studied by both radioactive and fluorescent 

 antibody techniques. Further studies were done 

 on the lymphocytes of patients with dyspro- 

 teinemias including agammaglobulenemia, mul- 

 tiple myeloma, and macroglobulenemia. In 

 cases of hereditary agammaglobulenemia both 

 heterozygotes and homozygotes were examined. 

 Data about the quantitative production of gam- 



312 



