In vitro immunization for the production of antigen-specific lymphocyte hybridomas

Production of a monoclonal antibody by in vitro immunization that recognizes a native chondroitin sulfate epitope in the embryonic chick limb and heart

We report the production of a monoclonal antibody (d1C4) by in vitro immunization that has immunoreactivity with a native chondroitin sulfate epitope in embryonic chick limb and heart. Murine lymphocytes were stimulated by direct exposure to unfixed, unsolubilized precartilage mesenchymal aggregates in high-density micromass culture derived from Stage 22-23 chick limb buds. Specificity of d1C4 reactivity was demonstrated by sensitivity of immunohistochemical staining to pretreatment with chondroitinase ABC or AC, preferential immunoreactivity with chondroitin-6-sulfate glycosaminoglycan (CS-C GAG) in ELISA, and competition of immunohistochemical staining with CS-C GAG. Immunohistochemical analysis of the expression of the d1C4 epitope revealed a striking localization of immunoreactivity in the extracellular matrix (ECM) of precartilage aggregates of chick limb mesenchyme in high-density micromass culture by 16 hr and the prechondrogenic limb core at Stage 23 in vivo. Immunoreactivity in both cultured limb mesenchyme and the embryonic limb continued through differentiation of prechondrogenic condensations into cartilage tissue. In the developing chick heart, d1C4 staining was found throughout the ECM of atrioventricular cushion tissue by Stage 25, but was localized to mesenchyme adjacent to the myocardium in the outflow tract cushions. There was an abrupt demarcation between d1C4-reactive intracardiac mesenchyme and unreactive extracardiac mesenchyme of the dorsal mesocardium in the Stage 22 embryo. This study demonstrates the efficacy of in vitro immunization of lymphocytes for the production of MAbs to native ECM constituents, such as CS-GAGs. Immunohistochemical data utilizing d1C4 suggest that CS-GAGs bearing this epitope may be important in early morphogenetic events leading to cartilage differentiation in the limb and valvuloseptal morphogenesis in the heart.

Sensory neurons regulate immunoglobulin secretion of spleen cells: cellular analysis of bidirectional communications between neurons and immune cells

The effects of primary sensory neurons in the dorsal root ganglia (DRG) on immunoglobulin (Ig)-secreting activity of spleen cells were investigated in culture. The conditioned medium (CM) of normal spleen cells stimulated DRG neurons to release neurokinin A which increased the number of Ig-secreting spleen cells. In contrast, the CM of concanavalin A-induced suppressor spleen cells induced the release of vasoactive intestinal peptide, an inhibitor of Ig secretion of spleen, from DRG neurons. These findings indicate that sensory neurons can help and suppress Ig secretion, and these bidirectional activities are controlled by the factors released from immune cells.

Monoclonal antibody that inhibits biological activity of a mammalian ciliary neurotrophic factor

Four monoclonal antibodies to a purified ciliary neurotrophic factor have been produced by a combination of in vivo and in vitro immunization of mouse lymphocytes. Three of the antibodies--3D12, an 1gA subtype, and 5G9 and 2B11, both IgM subtypes--bound to the single band on immunoblots of the purified factor. Of the four clones only one, 3D12, produced antibodies able to inhibit the biological activity of the neurotrophic factor in promoting the survival of ciliary neurones in dissociated culture.

Mouse polyclonal and monoclonal antibody to scrapie-associated fibril proteins

Antibody response in mice to scrapie-associated fibril proteins (protease-resistant proteins [PrPs]) was generated to different epitopes depending on the source of antigen. Mice responded differently to PrPs isolated from scrapie-infected animals of homologous (mouse) versus heterologous (hamster) species. An enzyme-linked immunosorbent assay established to monitor this antibody response in mice immunized with PrPs was unable to detect such a response in scrapie-infected mice. A monoclonal antibody (MAb), 263K 3F4, derived from a mouse immunized with hamster 263K PrPs reacted with hamster but not mouse PrPs. MAb 263K 3F4 also recognized normal host protein of 33 to 35 kilodaltons in brain tissue from hamsters and humans but not from bovine, mouse, rat, sheep, or rabbit brains. This is the first demonstration of epitope differences on this host protein in different species. The defining of various epitopes on PrP through the use of MAbs will lead to a better understanding of the relationship of PrPs to their host precursor protein and to the infectious scrapie agent.

Development of in vitro immunization in murine and human hybridoma technology

The development of in vitro immunization in murine and human hybridoma technology is reviewed. Special consideration is given to: technical aspects of in vitro immunization of mouse B cells; quality of antibodies produced by in vitro immunization; advantages of murine in vitro immunization; technical aspects of in vitro immunization of human B cells; and the advantages of human in vitro immunization and human monoclonal antibodies. Future developments likely to be made in this area of immunotechnology are outlined.