Isolation and characterization of c-fos-expressing murine bone marrow stromal cell lines supporting myeloid differentiation.

We have previously reported that constitutive expression of c-fos oncogene allows long-term proliferation of primary mouse bone marrow stromal cells favoring the granulocytic differentiation of myeloid precursors in an in vitro assay. Retrovirus-mediated gene transfer of the human c-fos gene was used here for immortalizing nine mouse bone marrow cell lines which were studied in detail. However, due to low expression of the ectopic c-fos gene, none of them showed characteristics of transformation as assayed by dependence upon serum for growth, the inability to form colonies in agar and contact inhibition.

The human T-cell receptor gamma variable pseudogene V10 is a distinctive marker of human speciation.

The V10 variable gene of the human T-cell receptor gamma locus (TCRG-V10), the only member of the subgroup III, has a structural defect which inhibits the splicing of the leader intron. We show that there is a single point mutation in the V10 leader donor splice site responsible for this situation and that this mutation is found in the different populations tested, indicating that V10 corresponds to a pseudogene in humans. We restored the splice site by mutagenesis and obtained correct splicing in vitro.

Growth-regulated expression of FKBP-59 immunophilin in normal and transformed fibroblastic cells.

Expression of many primary response cellular genes is observed during the early stages of transition from a resting G0 state to DNA synthesis. To identify gene products implicated in long-term response to growth factors, we have isolated genes sequentially activated several hours after serum stimulation of fibroblastic CCL39 cells. We report here the characterization of one of them as encoding the immunophilin of 56-59 kDa (FKBP-59), a component of the steroid receptor complex.

Cassette baculovirus vectors for the production of chimeric, humanized, or human antibodies in insect cells.

Plasmid cassette-transfer vectors pBHuC chi and pBHuC gamma l have been designed which enable the construction of recombinant baculoviruses directing the co-expression of complete immunoglobulin in insect cells. We describe the application of these vectors for the expression of a human/mouse chimeric monoclonal antibody of potential immunosuppressive clinical value derived from a mouse anti-human CD29 monoclonal antibody (Mu-K20). The chimeric K20 light and heavy chains produced in sf9 insect cells were correctly processed and assembled into a normal immunoglobulin which is secreted into the culture medium of infected cells.

Organization of the human immunoglobulin lambda light-chain locus on chromosome 22q11.2.

The maps of the human immunoglobulin heavy-chain and kappa light-chain loci have recently been completed. We have now completed a map of the human lambda locus (IGL) located on chromosome 22q11.2.

Inhibition of T cell activation with a humanized anti-beta 1 integrin chain mAb.

The murine anti-CD29 mAb K20 (Mu-K20) is known to bind to the beta 1 chain of the human integrins and to inhibit activation and proliferation of T cells, implying an important potential for in vivo immunosuppression. However, use of K20 as an immunosuppressant drug would be impaired by the immunogenicity of mouse mAbs in man. We have therefore engineered K20 into (1) a mouse/human chimeric mAb (Ch-K20) that comprises the human kappa/gamma 1C regions and the K20 V regions; and (2) a humanized mAb (Hu-K20) combining the complementarity-determining regions (CDRs) of the K20 mAb with human framework (FR) and kappa/gamma 1 C regions.

Molecular analysis of the T17 immunoglobulin CH multigene deletion (del A1-GP-G2-G4-E).

In the human, the order of the immunoglobulin heavy chain constant region (Ig CH) genes is the following: 5'-M-D-G3-G1-EP1-A1-GP-G2-G4-E-A2-3'. Extensive multigene deletions have been described in the Ig CH locus, some of these encompassing up to 160 kb. To date six different multigene deletion haplotypes have been identified, designated I to VI according to the chronological order of their being found: deletion I (del G1-EP1-A1-GP-G2-G4), II (del EP1-A1-GP), III (del A1-GP-G2-G4-E), IV (del EP1-A1-GP-G2-G4), V (del GP-G2-G4-E-A2), VI (del G1-EP1-A1-GP-G2).