Storage of human lymphocytes at room temperature

Advancing precision in histocompatibility and immunogenetics: a comprehensive review of the UCLA exchange program

Precise typing of human leukocyte antigens (HLA) is crucial for clinical hematopoietic stem cell and solid organ transplantations, transfusion medicine, HLA-related disease association, and drug hypersensitivity analysis. The UCLA Cell Exchange program has played a vital role in providing educational and proficiency testing surveys to HLA laboratories worldwide for the past 5 decades. This article highlights the significant contribution of the UCLA Cell and DNA Exchange Programs in advancing HLA antibody testing, genotyping, crossmatches, and, more recently, virtual crossmatches. Additionally, we discuss future directions of the UCLA Cell Exchange program to support histocompatibility testing to adapt to the fast-evolving field of immunotherapy, tolerance and xenotransplantation.

HLA typing from human donor eyes

A method for HLA-ABC and HLA-DR typing of human donor eyes using pigmented retinal epithelial and uveal cells cultured in the presence of human recombinant gamma-interferon is described.

Is serum the optimal source for HLA antibodies?

The cytotoxic reactivity of 18 predefined class I HLA serum antibodies was compared with that of antibody preparations containing anticoagulants. ACD-A, EDTA, 4% citrate and heparin plasmas all showed lower cytotoxicity than serum antibodies. Recalcification of both platelet-rich and platelet-poor ACD-A plasma did not fully restore the antibody reactivity, suggesting a detrimental effect of calcium chelation. This effect was exclusive of volume or of any platelet or plasma protein involvement. The changes in pH contributed to the lower reactivity and to the increased lympholytic effect, whereas adjusting the pH toward the serum value improved the reactivity. Heat-inactivated antibodies showed only a slightly reduced cytotoxicity. Heparin had the least effect of all anticoagulants on the reactivity, although in heparin there was a definite dose-dependent decline in cytotoxic titer which was probably related to anticomplementary activity. Calcium chelators, such as EDTA and citrate, showed marked cytotoxic inhibition at half the usual complement concentration. This effect was more pronounced when the anticoagulant and lymphocytes were incubated prior to cytotoxicity testing. At the complement concentrations used, the inhibitory effects of the citrate anticoagulants appeared to be primarily calcium-related. Inhibition tests, serial titrations and testing of varying calcium concentrations confirmed the superiority of serum as antibody source.

HLA and tropical splenomegaly syndrome in the Upper Watut Valley of Papua New Guinea

Tropical splenomegaly syndrome (TSS) develops as a result of an atypical immune response to recurrent malarial infection. In general a low prevalence disorder, in the Upper Watut Valley of New Guinea TSS affects more than 80% of the inhabitants. We have studied the association of antigens and haplotypes of HLA-A,B,C, DR, and DQ loci with the severity of TSS as judged by the degree of splenomegaly in 77 unrelated Watut. The study confirmed the previously observed lack of association of TSS with HLA-A and B locus antigens. By contrast, HLA-DR2 was found to be more frequent in patients with gross splenomegaly than in those with moderate splenic enlargement. No two-locus haplotypes were, however, found to be significantly associated with TSS.

HLA studies of Highland and Coastal New Guineans

The HLA profile of three New Guinean populations, two Highland (Asaro, Watut), and one Coastal is presented. The Highland populations are characterized by a low average number of alleles segregating at the HLA loci and also by a low mean value of heterozygosity at these loci. The genetic affinities of the two Highland groups with other Melanesian populations in the Pacific are remote. The Coastal group, on the other hand, shows strong similarities in its antigenic diversity and haplotypic combinations with other Melanesian populations. Nonetheless, the two Highland groups show significant divergence from each other in terms of allelic and haplotypic frequencies. Two different waves of migration settled in the Highlands of New Guinea between 10,000 and 15,000 years ago, and it is possible that the Watut, an Angan speaking group, represents the remnants of the first migration into the interior, whereas the Asaro, members of the Eastern Central family of the Trans-New Guinea phylum, arrived at a later date.

The influence of common variables on T cell subset analysis by monoclonal antibodies

Normal values for T cell subsets as defined by the most commonly used monoclonal antibodies of the OKT series were determined in a group of 142 unrelated normal individuals. In most age classes females had significantly greater portions of OKT3 and OKT4 antigen bearing lymphocytes and accordingly a higher T4/T8 index. The range of individual normal values within the control population was remarkably wide. Intra-individual differences between the T subset composition remained rather constant over a period of 2 months. Time of day, food absorption and physical exercise had no influence on the results of subset analyses. Storage of the blood sample and freezing of isolated lymphocytes can result in significantly reduced OKT3 and OKT4 positive cell numbers. If lymphocytes were isolated soon after the blood was taken and resuspended in a stabilization medium they exhibited only minimal change.

Loss of HLA-C locus specificities from stored lymphocytes and de novo synthesis following incubation at 37 degrees C

The variable expression of the C locus specificities at the cell surface is a major problem in HLA typing and the phenomenon was clearly documented by the International Cell Exchange Program. In contrast with HLA-A and -B, the C locus specificities are readily lost from cells following storage at room temperature for a few days or in overnight incubation at 37 degrees C in the presence of protein synthesis inhibitors. These specificities can be made to reappear by making the cells metabolize at 37 degrees C for 8 to 20 h in nutrient medium. Sixty-nine per cent of the positive C locus reactions lost after 7-day storage at room temperature were recovered after overnight incubation at 37 degrees C. The reappearance was dependent on protein synthesis since presence of cyclohexamide during incubation completely blocked the recovery. A simple overnight incubation is very useful in enhancing C locus expression on older cells.

Cellular immunity in Guamanians with amyotrophic lateral sclerosis and Parkinsonism-dementia

To test the hypothesis that host resistance factors may be abnormal in Guamanians in whom amyotrophic lateral sclerosis and Parkinsonism-dementia develop, cellular immunity was evaluated in both diseases and compared to that of Guamanians with other nervous-system diseases, normal adult Guamanians and non-Guamanians with amyotrophic lateral sclerosis and Parkinsonism. Diminished responses to skin-test antigens, lymphopenia, diminished per cent and total T cells and, less frequently, decreased mitogen responses were seen in Guamanian patients with amytorophic lateral sclerosis and Parkinsonism-dementia but not in the other patient or normal groups. Guamanian patients with amyotrophic lateral sclerosis and diminished cellular immunity had an increased frequency of HLA-Bw35 (P less than 0.005) and shorter mean duration of disease (P less than 0.05) than those with normal cellular immunity. In Parkinsonism dementia diminished cellular immunity was less strongly associated with HLA-BW35 (P less than 0.05) and was not associated with differences in duration of disease. Normal Guamanians and those with other nervous-system diseases showed no association of diminished cellular immunity with HLA-Bw35. The association appeared disease-related, with onset concomitant with the neurologic expression of Guamanian amyotrophic lateral sclerosis and Parkinsonism-dementia.

Reproducibility, efficacy and methodology of mitogen-induced lymphocyte transformations by the whole blood assay

For the past few years, the whole blood culture method has been scrutinized for its usefulness and reproducibility in evaluating the immunologic status of patients. This method, used in our laboratory mainly screening specimens for evidence of immunodeficiencies, has been systematically evaluated for reproducibility, and factors affecting normal response through testing specimens from over 70 normal persons. Three mitogens (phytohemagglutinin, Concanavalin A, and pokeweed) were studied; peak time responses occurred later than in the separated cell culture method, and they were different for each mitogen. The dose response curves also depended on the mitogen tested, with pokeweed giving a sharp curve and the others a broad plateau. The harvesting procedure was studied by varying reagents and was optimized for speed and efficiency. The mononuclear cell count of the specimen had little effect on the results as long as it remained less than 3.5 X 10(6)/ml. The results for all mitogens followed a similar distribution curve irrespective of whether the results were expressed as cpm or cpm divided by the mononuclear cell count. The use of the stimulation ratio method to express results was less satisfactory. The mean coefficient of variation for all triplicate samples remained 20% or less and for all conditions tested. In evaluating the immunodeficient patient, the whole blood culture method was found to be equally as informative and easier to perform than the separated cell method.

Some methodological studies on effector cells in the lymphocyte-dependent cytotoxic antibody assay

A method of direct freezing was found to be reliable for storage of the effectors for the LDA assay, though there is a considerable loss of cells. In order to get immunologically active K cells after thawing, an important step is to leave the cells to recuperate overnight in an appropriate medium before use. A short-term storage of fresh effectors is also possible. The use of a pool of effector cells from a minimum of 3 random blood donors obviates the selection of HL-A types furthermore permits a saving of the amount of serum used. Enrichment of a B cell population by removing the cells capable of forming spontaneous rosettes with SRBC was not found to enhance cytotoxicity. Pretreatment of cells with pronase, trypsin and neuraminidase did not significantly enhance their effector activity, while papain treated cells showed a systematically increased specific lysis.