Studies on the growth of the phage T4 in cell division mutantsa DV1211 and AD651 of Esachechiria coli AT normal and high temperatures

Os mutantes DV1211 e AD651 da divisäo celular em E. coli apresentam reduçäo na taxa de adsorçäo do fago T4 à sua superfície celular. O crescimento deste fago nos referidos mutantes é normal, porém , a 42 graus C apresenta um considerável retardo na sua liberaçäo por lise celular. O fenômeno parece estar associado à uma alteraçäo termoinduzida no mecanismo de maturaçäo do fago T4

Defective humoral immunity in pediatric acquired immune deficiency syndrome.

Specific antibody production was assessed in six young children with the acquired immune deficiency syndrome (AIDS). All patients were immunized with bacteriophage phi X 174, a T cell-dependent neoantigen. In addition, antibody responses to pneumococcal vaccine and tetanus toxoid, lymphocyte responses to mitogens, and serum immunoglobulin levels were determined. Polyclonal hypergammaglobulinemia was documented in three patients. Responses to bacteriophage phi X 174 were abnormal in all patients: primary responses were blunted, secondary responses were markedly decreased, and the class switch (IgM-IgG) was absent in five of six patients. Antibody formation to pneumococcal vaccine and tetanus toxoid was also diminished. Lymphocyte mitogenic responses to phytohemagglutinin, concanavalin A, pokeweed mitogen, and staphylococcal Cowan A were generally decreased. These findings confirm that pediatric patients with AIDS have significant abnormalities in humoral immunity. Dysfunction of both T cells and B cells plays a role in the resultant poor specific antibody production.

Studies on phage internal proteins. VI. Interaction of bacteriophage T4 internal proteins with T4 DNA in vivo and in vitro.

Internal proteins are basic proteins bound to the DNA of T4 coliphage. Centrifugation in sucrose gradients was employed to isolate DNA-internal proteins complexes formed in vitro. Polyacrylamide gel electrophoresis of radioactive internal proteins in the presence of sodium dodecyl sulfate followed by autoradiography of the gels was used to identify the DNA-bound proteins and to determine their respective abundance in these complexes as well as in the bacteriophage head. The internal proteins were found to bind to the phage DNA (in vitro experiments) at the same ratio as that of internal proteins associated with the viral DNA within the phage head (in vivo binding).