Augmentation of the antibody response by hapten help: I. Dominant genetic control

The objective of the present work was to characterize those genetic factors that determine susceptibility to “hapten help,” i.e., the augmentation of B-cell responses by hapten-reactive T cells. After mice had been sensitized to the hapten azobenzenearsonate (ABA), one of two approaches was used to assay hapten help. In the first, circumvention of tolerance to low doses of bovine γ-globulin (BGG) was augmented in CBA but not in C57BL/6 mice, as measured by serum anti-BGG antibody after challenge with ABA-BGG. Second, similar strain differences but on a larger scale were demonstrated in the anti-BGG plaque-forming cell (PFC) response of spleen cells from hapten-primed nontolerized mice after challenge with ABA-BGG. Results with the F1-hybrid of a cross between a high responder and a low responder for hapten help demonstrated that high responsiveness is dominant. Experiments with recombinant inbred mice from high- and low-responder progenitor strains suggested that hapten help is associated not with the major histocompatibility complex (H-2) so much as with minor histocompatibility antigens such as H-22 and/or H-24, both of which are on chromosome 7.     

RNA extracts of lymphoid cells sensitized to DNP-oligolysines convert nonresponder lymphoid cells to responder cells which release migration inhibition factor

Strain 13 nonresponder peritoneal exudate cells were converted to responder status to α or ?,DNP-oligolysines after incubation of the cells with RNA extracts prepared from responder guinea pigs skin test sensitive to these synthetic antigens. The conversion of nonresponder strain 13 cells was assessed by the direct cell migration inhibition correlate of delayed hypersensitivity. Nonresponder cells were not converted by RNA extracts prepared from unimmunized responder guinea pigs or from non-responder strain 13 guinea pigs previously injected with DNP-oligolysines. Thus, it seems possible to correct immunological unresponsiveness in vitro in spite of a specific genetically determined deficiency of the immune response related to the Ir gene.     

Features of Membrane Receptors in Bacterial Multiplication Process and Necessary Conditions for Phage Infection of Bacteria

According to the obtained experimental results, the thermal shock (from 37 to 53 °C) not only stops the multiplication process of Escherichia coli bacteria, but also causes bacterial titer to decrease gradually. After this period lasting up to 1 hour, the bacterial cells continue to grow. A similar type of response was observed when bacteria were subjected to acid shock. Increasing acidity of media leads to decrease of bacterial growth process, and finally, their titer curve sharply falls over time. Also, interesting results were obtained about necessary conditions for infecting the bacteria by phages. Particularly, DNA injection from phages into bacterial cells requires most of corresponding bacterial membrane receptors to be occupied by phages. We suppose that this occurs due to autocrine phenomenon when the signaling molecules block the DNA ejection from phage particles. This effect lasts until a certain number of phage particles are attached to the membrane. After that, DNA injection from phage head into the cytoplasm takes place and the process of bacterial infection begins. The real number of phages in a stock is by several orders higher than the number of plaque-forming units in a given stock, which is determined by a classical double-layer agar method.     

Smoothelin-like 2 Inhibits Coronin-1B to Stabilize the Apical Actin Cortex during Epithelial Morphogenesis

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T4 bacteriophage as a phage display platform

Analysis of molecular events in T4-infected Escherichia coli has revealed some of the most important principles of biology, including relationships between structures of genes and their products, virus-induced acquisition of metabolic function, and morphogenesis of complex structures through sequential gene product interaction rather than sequential gene activation. T4 bacteriophages and related strains were applied in the first formulations of many fundamental biological concepts. These include the unambiguous recognition of nucleic acids as the genetic material, the definition of the gene by fine-structure mutation, recombinational and functional analyses, the demonstration that the genetic code is triplet, the discovery of mRNA, the importance of recombination and DNA replications, light-dependent and light-independent DNA repair mechanisms, restriction and modification of DNA, self-splicing of intron/exon arrangement in prokaryotes, translation bypassing and others. Bacteriophage T4 possesses unique features that make it a good tool for a multicomponent vaccine platform. Hoc/Soc-fused antigens can be assembled on the T4 capsid in vitro and in vivo. T4-based phage display combined with affinity chromatography can be applied as a new method for bacteriophage purification. The T4 phage display system can also be used as an attractive approach for cancer therapy. The data show the efficient display of both single and multiple HIV antigens on the phage T4 capsid and offer insights for designing novel particulate HIV or other vaccines that have not been demonstrated by other vector systems.