Antibodies cell cooperation

In an immune response, antibodies are produced and secreted by the B-lymphocytes in conjunction with the T, cells. In the majority of hapten-carrier systems, the B cells end up producing antibodies that are specific for both the hapten and the carrier. In these cases, the T lymphocytes will have specific-binding domains on the carrier, but will not recognize the hapten alone. In a kind of synergism, the B- and T-cells cooperate to induce a hapten-specific antibody response. After such an immune response has taken place, if the host is subsequently challenged with only the hapten, usually it will respond by producing hapten-specific antibodies from memory cells formed after the initial immunization. For a review of immunobiology (see Janeway, 2004). 

Roelants, G. E., Askonas, B. A. Cell cooperation in antibody induction. The susceptibility of helper cells to specific lethal radioactive antigen. Europ. J. Immunol. 1, 151-157 (1971). 

In summary, the in vivo protective effects of Tyv-specific antibodies, exclusion and immobility, can now be effectively studied using an in vitro model of the intestinal epithelium. Larvae are prevented from entering epithelial cells by caps of immune complexes or by binding of antibody to Tyv in the absence of immune complex formation. These effects would correlate with exclusion of larvae from epitheha observed in passively immunized rats. Larvae are encumbered as they migrate within epithelial monolayers, an effect that may correlate with immobility of larvae observed in vivo. It is reasonable to conclude that in the animal host the different effects work in combination, most iikeiy in cooperation with innate host defences, to cause nematode expuision from the intestine. 

Hanjan, S. N. S., Kearney, J. F., and Cooper, M. D. (1982) A monoclonal antibody (MMA) that identifies a differentiation antigen on human myelomonocytic cells. Clin. Immunol. Immunopathol. 23,172. 

Cornelia, K., Nakamura, M., Melnik, K., Chosy, J., Zborowski, M., Cooper, M. A., et al. (2001) Effects of antibody concentration on the separation of human natural killer cells in a commercial immunomagnetic separation system. Cytometry 45, 285. 

More recently, this model has undergone substantial modification. First, it became apparent from biosynthetic studies on cells in culture that there were two distinct B chains, B1 and B2 (Cooper et al., 1981), which were not well resolved in laminin prepared from the EHS tumor. Analysis of the stoichiometry of the chains produced in these systems suggested that the laminin molecule contained one A, one Bl, and one B2 chain (Fig. 9). Studies with a monoclonal antibody specific for the A chain indicated that the A chain formed part of the short arm as well as the long arm of laminin (Palm et al., 1985). The assembly of the molecule appears to proceed in discrete steps, with the initial assembly of a B1-B2 dimer linked by disulfide bonds to which an A chain is added (Morita et al., 1985 Peters et al., 1985). 

As discussed below, new knowledge about cell membrane ultrastructure emphasizes the importance of a layer of stranded glycoprotein material external to the lipid bilayer in a wide range of functions. These functions range from modulation of transmembrane ion fluxes through membrane ion channels to formation of receptor sites for antibody molecules. These capabilities depend in great measure on the polyanionic terminal structure of these stranded protrusions. Clearly, the two examples cited present extremes in the complexities of membrane organization. Nevertheless, both types of process exhibit similar sharp transitions as a function of temperature that are consistent with cooperative processes. 

For most antigens, the production of antibody (immunoglobulin) is based on the cooperative interaction of two types of lymphocyte, called T-cells (thymus-derived) and B-cells (bone marrow-derived). The T-cells, preprimed with macrophage-presented antigen, stimulate the B-cells to secrete copious quantities of antibody. However, on the basis of animal studies, such polysaccharide antigens as the type III pneumococcal polysaccharide have been considered to be T-cell-independent, as they are capable of triggering B-cells to produce antibody (IgM) in T-cell-deficient mice.167 These studies also indicated... 

A study by LeBlond and Marcel (1991) using monoclonal antibodies supports the concept of a biological role for the direct interaction of amphipathic helices with plasma membranes these authors suggest that the optimum uptake of. . . HDL. . . requires the. . . cooperative binding of the amphipathic a helical repeats [of apoA-I] to HepG2 cell membranes. Consistent with direct interaction of amphipathic helixes with plasma membranes is the fact that apoA-I, apoA-II, and apoA-lV bind equally well, even though apoA-11 is made up almost entirely of class A amphipathic helical domains (Fig. 7). 

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