We have examined the ability of hCD4 to interact functionally with mouse class II MHC molecules using the mouse T cell hybridoma BI-141, specific for beef insulin. We have previously shown that expression of mouse CD4 results in a marked enhancement of IL-2 release by BI-141 cells in response to beef insulin or, in a cross-reactive response, to pork insulin, on the appropriate mouse APCs. We no...

Five hybridoma T cell lines were prepared by fusion of Ts3 cells with the BW 5147 thymoma. The culture supernatants from these T cell hybrids contained a factor, TsF3, which specifically suppressed 4-hydroxy-3-nitrophenyl acetyl hapten (NP(-hapten cutaneous sensitivity responses. The properties of this new series of hybridoma factors was compared with those of two previously characterized types...

Myeloma-spleen cell hybrids (hybridomas) producing antibody to mouse immunoglobulin allotypes have been labeled with fluorescent microspheres coupled with myeloma protein antigens. The ratio of specific to nonspecific microsphere binding by viable hybridoma cells was about 100:1. By using a modified fluorescence-activated cell sorter (FACS), selected hybridoma cells in a mixture have been sorte...

Identification and quantification of immunogenic peptides and tumor-derived epitopes presented on MHC-I molecules are essential for basic studies and vaccines generation. Although lymphocytes derived from transgenic mice can serve as sensitive detectors of processes of antigen presentation and recognition, they are not always available. The use of cell lines might be extremely useful. In this s...

Homologous recombination vectors were designed to convert murine hybridoma cell lines expressing IgG3, IgG1, or IgG2a heavy chains into chimeric human IgG1 producers. These conversion vectors included homology both upstream and downstream of the target sequences and consistently resulted in a higher frequency of successful gene targeting than an insertion vector bearing a single region of homol...

We have examined the positive influence of human constant regions on the folding and bacterial expression of active soluble mouse immunoglobulin variable domains derived from a number of catalytic antibodies. Expression yields of eight hybridoma- and myeloma-derived chimeric Fab fragments are compared in both shake flasks and high density fermentations. In addition the usefulness of this system...

Osmolarity is an important process variable during the cultivation of mammalian cells in vitro. Cell culture medium is designed to have osmolarity in the range of 260 and 320 milliosmoles (mOsm), basically to mimic the osmolarity of serum at 290 mOsm/kg. Fragmented information on the response of hybridoma cells to elevated osmolarity is available. A decrease in cell growth and an increase in an...

We demonstrate that murine myeloma cells can efficiently mediate homologous recombination. The murine myeloma cell line J558L was shown to appropriately recombine two transfected DNA molecules in approximately 30% of cells that received and integrated intact copies of both molecules. This activity was then exploited to direct major reconstructions of an endogenous locus within a hybridoma cell ...

Peripheral blood lymphocytes and splenocytes of patients with autoimmune disease were used to prepare human-human hybridomas that produce autoantibodies. Because exogenous immunization was not used, the hybridoma antibodies were derived from B cells that spontaneously produced autoantibodies. 108 hybrids grew from 4,254 wells (2.5%). Optimal conditions for obtaining hybridomas with the GM 4672 ...

The encephalomyocarditis virus (EMCV) leader sequence is responsible for efficient, cap-independent translation initiation from the viral RNA. It has been used to increase the expression of internal coding regions on polycistronic mRNA encoded by recombinant DNA constructs. We have designed a sequence-replacement-type vector for targeting to immunoglobulin heavy-chain loci in hybridoma cells. H...