HLA-D typing with lymphoblastoid cell lines. VI. Rationale and goals of data reduction

This report documents various characteristics of HLA-D typing by mixed leukocyte culture reactions when lymphoblastoid cell lines (LCLs) are substituted for peripheral blood lymphocytes as the stimulator cells. It also provides the rationale for designing the computer program described in the subsequent report. In such experiments, each donor to be HLA-D typed is stimulated with a panel of 30-50 HLA-D homozygous LCLs, each defined HLA-D allele being represented by several different human homogygous typing cells (LCT-HTCs). Variability in the strength of eahc donor's general response and in the strength of stimulation by each LCL-HTC makes it necessary to normalize raw data before the responses of various combinations can be compared and typing responses distinguished from non-typing responses. The autologous response and its equivalent effect among allogenetic combinations, the so-called "autologous-stimulation" effect, must also be distinguished from true allogeneic responses. The latter has been accomplished by "modelling," as described in the subsequent report. EBV-negative donors can also be HLA-D typed by this method despite the EBV-positivity of the LCL-HTCs. Preliminary analyses suggest that the HLA-D alleles defined by this method appear to segregate with appropriate haplotypes in family studies.

Suppression of lymphoblastoid cell line proliferation by antisera to HLA-DR and other HLA antigens

We have observed that certain antisera to HLA antigens suppress the in vitro proliferation of lymphoblastoid cell lines. An antiserum to HLA-B8 demonstrated suppressor activity associated with the presence of B8 antigen on the target LCLs; this activity was removed by absorption with platelets or with B8-positive LCLs. An antiserum to HLA-DRw7 suppressed proliferation of all six DRw7-positive LCLs and none of 12 DRw7-negative LCLs; this activity was removed by absorptions with three DRw7-positive LCLs, each representing a different HLA-D allele (i.e. Dw7, 10 and 11); it could not be removed by triple serial absorptions with platelets from multiple-donor pools. These experiments indicate that the suppressor activity of this serum is specifically associated with antibodies to DRw7. Our model of LCL growth suppression by HLA antisera is easily manipulated and provides a definitive tool for further characterizing HLA antigens and antisera in a complement-independent system.

Membrane receptors and their redistribution in lymphoproliferative disorders

Lymphoid cells from 20 patients with lymphoproliferative disorders, including chronic lymphocytic leukemia, hairy cell leukemia, Sezary syndrome, lymphoma, and lymphadenitis, were studied for redistribution of surface membrane immunoglobulins (SmIg) and concanavalin A (Con-A) receptors. Fluorescein-labeled polyvalent goat anti-human immunoglobulin and fluoresceinated concanavalin A were used as ligands. Results were similar with both ligands. The highest percentage of capping of ligand-membrane receptors was noted in mononuclear cells from patients with "hairy" cell leukemia: from 24% to 90%. These cells showed moderate to marked fluorescein activity and were able to cap within 15 min at 4 degrees C. Chronic lymphocytic leukemia cells showed a weak fluorescein stain with a very low percentage of cells (0%--16%) capping. Lymph node cells from patients with lymphoma demonstrated moderate to strong fluorescein activity with only an average of 3% of the cells capping; while lymphoid cells from patients with lymphaedenitis showed an average of 27.5% capping and moderate fluorescein activity. Capping of Con-A receptors in mononuclear cells from patients with Sezary syndrome was poor (0%--14%) with moderate fluorescein intensity. This report demonstrates difference in density and mobility of binding sites for SmIg and Con-A on the surface membrane of lymphoid cells from various subclasses of lymphoproliferative disorders. These differences may assist in the differential diagnosis and classification of these conditions.

HLA-D typing with lymphoblastoid cell lines. VII. A computer program for data analysis

When lymphoblastoid cell lines (LCL) are substituted for peripheral blood lymphocytes from human typing cell donors in HLA-D typing experiments, a data analysis program must be designed to distinguish the effect of allo-reactivity from those peculiar to LCL, mainly the "autologous-stimulation" effect. The computer program described in this report was created specifically for such an analysis. The rationale for the design of this program is presented in the preceding report (see this issue).

Sézary syndrome. Tartrate-resistant acid phosphatase in the neoplastic cells

Tartrate-resistant acid phosphatase has been known to be of diagnostic value in hairy cell leukemia. However, occasionally neoplastic cells of other varieties of lymphoproliferative disorders may contain tartrate-resistant acid phosphatase. The authors have studied four patients with Sézary syndrome who had typical cutaneous lesions with extensive lymphoid infiltrates and circulating atypical E-rosetting lymphoid cells. The abnormal Sézary cells accounted for 23-69% of the peripheral mononuclear cells and often showed convoluted or folded nuclei. These cells in all four patients were strongly positive for acid phosphatase resistant to tartaric acid inhibition. Enzymatic cytochemical studies for acid phosphatase with and without tartrate may be helpful in the differential diagnosis of cutaneous T-cell lymphomas from variants of chronic dermatitis.

HLA-D locus typing in ankylosing spondylitis and Reiter's syndrome

HLA-D typing of 44 patients with ankylosing spondylitis (AS) and 31 patients with Reiter's syndrome (RS) did not show increased frequency of any particular Dw allele in either population of patients as compared to controls. Such studies also allowed each patient's general response to be compared with other general responses within each experiment. Contrary to reports of diminished lymphocyte responses in AS patients, hyperresponsiveness in both AS and RS patients was found.

HLA--D typing with lymphoblastoid cell lines. IV. Allelic relationships

Responses of approximately 200 persons were measured by mixed leukocyte cultures against 41 lymphoblastoid cell lines which were thought to be homozygous for HLA--D (i.e. LCL-HTCs). These responses were standardized by computer analysis and the resultant Interaction Indices for each LCL-HTC were compared with those of every other LCL-HTC in a correlation matrix of 861 independent analyses. Only those analyses involving LCL-HTCs of defined HLA--D types are reported here. In general, these studies confirmed many allelic relationships of reputedly similar LCL-HTCs; however, several unexpected groups of correlations suggested that groups Dw1 and 3 overlap to form Groups "1a-3," "1b-3" and "true 3." The "1b-3" group also included Dw8. Segregation of the "1b-3" allelic group was also observed in a family study. These preliminary analyses suggest a working model for further investigation of HLA--D allelic relationships (Fig. 3). On the other hand, they may also be interpreted to suggest that "typing" with LCL-HTCs may be controlled by a separate HLA locus which is closely related to, but distinct from, HLA--D.

New groups and segregant series among B-cell alloantigens of the Merrit system. A study of leukemia cells, peripheral B cells, and lymphoblastoid cell lines

On the basis of reactions with a chronic lymphatic leukemia cell panel, evidence for 6 new specificities of the Merrit B-cell alloantigenic system in man is presented, bringing the number of provisionally defined specificities to 19. These can be roughly divided into two segregant series. The system is well represented on both homozygous and heterozygous B-type lymphoblastoid cell lines. In the cell lines some specificities show a suggestive but inexact correlation with HLA-D locus factors. This correlation is represented also on peripheral blood B cells, on the non-T variety of acute lymphatic leukemia cells, and on acute myeloid leukemia cells. Although great similarities exist, each of the cell populations may manifest differences other than or in addition to mere differences in B-cell antigen frequencies.

Simplification of B-cell antisera of the Merrit system with platelets and lymphoblastoid cell lines

Human sera with anti-HLA and anti-Merrit B-cell reactivities were absorbed with different volumes of a pool of packed outdated human platelets obtained from 237 donors. After absorption, each serum was tested against a panel of CLL cells and normal unfractionated peripheral blood lymphocytes that had given positive reactions with the same serum prior to absorption. The optimal platelet volume for complete absorption of anti-HLA and full preservation of anti-Merrit B-cell activities in these sera was found to be 1/10 to 1/5 of the volume of serum. Higher volumes of packed platelets, especially over 1/1, in most instances reduced anti-B-cell activity "nonspecifically." Among the platelet absorbed sera, those showing no HLA and strong anti-Merrit B-cell cytotoxicity were used for cross-absorption studies with cultured human lymphoid cell lines. Multi-specific anti-Merrit sera could be simplified by this method. Cultured lymphoblastoid cell lines represent a valuable resource, since large volumes of cells may be needed for absorption and simplification of human sera containing allogeneic B-lymphocyte antibodies.

The merrit alloantigenic system of human B lymphocytes: evidence for thirteen possible factors including one six-member segregant series

An analysis of the typing results of a 70-member chronic lymphatic leukemia B cell panel revealed evidence for 13 possible groups of the Merrit alloantigenic system. Six of these appeared possibly allelic and may represent a segregant series. The CLL panel was also fully typed for HLA and some degree of linkage dysequilibrium between Merrit and HLA seemed apparent from the data. Merrit antibodies can be absorbed out with selected surface membrane immunoglobulin (SMIG)-positive normal lymphocytes and less so or not at all with E rosette-forming T cells or Fc-positive SMIG-negative lymphocytes.

Possible use of established cell lines for MLR locus typing

MLR histocompatibility typing was performed by in vitro stimulation of lymphocytes from various persons with fresh lymphocytes (irradiated) or with lymphoblostoid cell lines (mito-mycin-treated) derived from donors homozygous at the MLR locus. MLC responses to both types of stimulation correlated strongly suggesting that a) established lymphoblastoid line cells can express products of the MLR loc and b) fresh lymphocytes can be replaced by these long term lines in MLR typing. Two lines (LV-B and MS-B) derived from two MLR homozygous donors (lv and MS) were used throughout these experiments. It is possible that as additional lines are established from such MLR homozygous donors, a panel of typing cells could be created which would serve to standardize MLR typing and allow selection of unrelated but histocompatible donors for transplantation.

Comparison of the allospecific and viral-specific immune responses to irradiated versus formaldehyde-fixed allogeneic Moloney lymphoma cells in CBA mice

Two groups of adult CBA mice were immunized with 10-7 allogeneic Moloney lymphoma (YAC) cells. These YAC (H-2a) cells, which were either irradiated with 6000 R (Group i) or were formaldehyde fixed (Group II), were injected i.p. at weekly intervals for 3 weeks. Four days following the last injection, sera and lymphocytes were collected and tested in vitro for activity against either allospecific antigens (H-2d target cells) or viral-specific antigens, namely, Moloney leukemia virus (MLV). Both groups of animals developed measurable cellular and humoral immunity to the virally determined antigens. However, only the animals in Group i, immunized with irradiated cells, developed detectable immunity to H-2d. Immune and control lymphocytes were tested in microcytotoxicity tests and by 51Cr release. Antibody was assessed by complement-dependent cytotoxicity, indirect membrane immunofluorescence, virus neutralization, and antibody-dependent lymphocyte cytotoxicity. Group I serum, which had both anti-MLV and anti-H-2 antibodies, was absorbed with either living or formaldehyde-fixed YAC cells. The living cells were able to remove both H-2 and MLV antibodies. On the other hand, the formaldehyde-fixed cells removed no H-2 antibody but were able to remove MLV antibody, although less efficiently than living cells. These data indicate that formaldehyde fixation selectively impaired the H-2 antigens, leaving the viral antigenicity relatively intact. Differences between the immune responses to MLV-determined antigens and to H-2 antigens were demonstrated in many of the parallel in vitro tests.