In the past, the analysis of primitive human hematopoietic progenitor cells with repopulating activity was limited by lack of appropriate in vitro assay systems. It was recently shown that cobblestone area-forming cells (CAFC) giving rise to cobblestone areas after 5 weeks in long-term marrow cultures (LTMC) represent a population of pluripotent progenitor cells with long-term marrow-repopulati...

An interesting culture obtained by limiting dilution is less likely to be monoclonal than a random viable culture. Current practice using limiting dilution to establish monoclonal lines of interesting recombinant DNA or hybridoma-derived organisms overestimates the probability that promising cultures are monoclonal, resulting in inadequate dilutions, with the need for additional subcloning and ...

Mammary reconstitution assays can be used to measure the stem cell frequency within an epithelial population by transplanting increasingly diluted single-cell preparations of the population of interest. There are fundamental steps in the single-cell isolation protocol which are directly related to the number of single epithelial cells obtained. Once single-cell suspensions have been obtained, s...

background: pan-igg specific monoclonal antibodies (mabs) are essential tools for assessment of humoral immunity, immune deficiency and gammopathy. in this study, four hybridoma clones producing mabs with different specificities for human igg isotypes were established. methods: splenocytes from balb/c mice immunized with fc fractions of human igg were fused with sp2/0 myeloma cells. hybridoma c...

Effector T cell responses rely on a phenotypically and functionally heterogeneous population of cells. Whether this diversity is programmed before clonal expansion or in later phases as a result of stochastic events or asymmetric cell division is not fully understood. In this study, we first took advantage of a sensitive in vitro assay to analyze the composition of single CD8(+) T cell progenie...

We have previously reported the development of in vivo 9.3 Ì 10 cells. This was significantly higher than the frequency of 1 SRC in 3.0 Ì 10 adult BM cells or 1 in 6.0 Ì 10 functional assays for primitive human hematopoietic cells based on their ability to repopulate the bone marrow (BM) mobilized peripheral blood (PB) cells from normal donors. Mice transplanted with limiting numbers of SRC wer...

To evaluate the potency by which human T cells are targeted and activated by bispecific monoclonal antibodies (BsAbs) t o lyse tumor cells, a clonogenic assay was developed. The efficacy of a CD3xCD19 BsAb binding to both the CD3 T-cell antigen and the CD19 B-cell antigen was already proven in "Cr-release assays and in 3-day activation cultures. To achieve more quantitative results, a 14-day c...