[Degradation of the insecticide parathion in soil]

Degradation of the insecticide Parathion in four types of soil from the Northeast of Brazil has been studied using radiometric techniques. In all the soil samples, sterilized or not, metabolites were detected with Rf values of 0.00 and 0.17 respectively--Silica Gel 60 F254 tlc plates (Merck); solvent system: hexane-acetone (4:1, v/v)--. However, 14CO2 was formed only with the non-sterilized soils and this was independent of the use or not of organic fertilizer. These results suggest that the two metabolites, mentioned above, are formed by a predominantly non-biological pathway, where as the formation of carbon dioxide requires the participation of the microbial flora of the soil. Analysis of the interaction of 14C-Parathion with soils shows that the extent of degradation of this insecticide is modified by adsorption on the soil particles.

T cell receptor beta chain gene rearrangements in leukemias with immature T cell phenotype

The arrangements of the T cell receptor (TCR) beta genes were studied in leukemias with immature T cell phenotype. Three cases of acute lymphocytic leukemia (ALL) and one case of chronic myelocytic leukemia in blastic crisis (CML-BC), which expressed only Tp40 antigen of cluster of differentiation (CD) 7 without erythrocyte rosette receptor (E), did not show rearrangements of TCR beta chain genes. Two of 5 ALL cases which expressed an additional T cell antigen, T1 of CD5, showed rearrangements of TCR beta genes. Two cases of CML-BC expressing T1 and Tp40, however, had unrearranged TCR beta genes. The results altogether showed that a part of E- T1+ Tp40+ ALL cases is of T cell origin.

Multiple epitopes on a single DQ molecule from the DQw3-carrying haplotypes

Multiple polymorphisms on the DQ molecule(s) have been detected by monoclonal antibodies (MoAbs). Among these, TA10 and IIB3 have been described as two new alleles in the DQ region other than the conventional DQw1-w3 allelism. The TA10 specificity is DQw3-related and is in linkage disequilibrium with DR5 and weakly associated with DR4. The IIB3 specificity is DQw1-related and is in linkage disequilibrium with DR2, DR4, DRw9 and DRw13. Thus, the DQw3-carrying haplotypes are either positive with TA10 or IIB3. The molecular and topological analysis has revealed that both TA10 and IIB3 determinants were expressed on a single DQ molecule that also carried the DQw3 determinants on DR5 and DR4 cell lines, respectively. Thus, a single DQ molecule generated multiple epitopes detected by alloantisera and/or MoAbs at least on the DQw3-carrying haplotypes. These would be useful for unraveling the largely unknown functions of the DQ class II molecules.

Molecular characterization of three HLA class II molecules on DR4 and DRw9 haplotypes: serologic and structural relationships at the polypeptides level

By using alloantisera, three distinct HLA-D/DR region-encoded class II molecules were identified from cells carrying the HLA-DR4 and DRw9 haplotypes. Both DRw-53 and DQw3 molecules that bear the "supertypic" specificity were isolated independently from the DR antigen. The light chains of the DR4 antigens from different HLA-D types were distinct from one another, whereas the DRw53 molecules had identical charge and molecular weight in both heavy and light chains. On the other hand, the DQw3 molecules from the DR4 cell lines (Dw4 and Dw 10) were apparently identical but were polymorphic at least in the light chains among the DR4, DR5, and DRw9 haplotypes. In addition, monoclonal antibodies which specifically precipitate DR4 and DQw3 molecules have been isolated. The variable extent of homogeneity and diversity of three class II molecules may aid in our understanding of the role of class II antigens in the human immune regulation.

Defective expression of HLA class I antigens: a case of the bare lymphocyte without immunodeficiency

A case of the bare lymphocyte without apparent immunodeficiency was observed in a 33-year-old woman who had no history of severe infections but suffered from sino-bronchial disease. No HLA-A and -B antigens (class I antigens) were detected at the cell surface of lymphocytes, granulocytes, and platelets, but they were expressed, although at a reduced level, on the cultured B lymphoid cell line. T lymphocytes were normal in number and in the relative proportion of T4/T8 and responded to mitogens but not to PPD and candida. HLA-DR antigens (class II antigens) were present on B lymphocytes and showed intermediate MLR-stimulatory capacity, which made it possible to deduce the patient's HLA genotype. She was found to be homozygous at consanguinity for HLA-A, -B, and -DR antigens. The numbers of B lymphocytes, immunoglobulins, and complements were all in the normal range; there was, however, a low level of IgM. Two-dimensional gel analysis of class I antigens revealed the presence of normally expressed beta-2 microglobulins (B2M) and an apparently single set of class I heavy chains, allowing us to consider two alternative cellular mechanisms in this defect; the presence of one abnormal class I structural gene and the regulatory mechanism that acted in cis were suggested.

Two-dimensional gel analysis of a second family of class II molecules by polymorphic HLA-DR4,5, and w9 monoclonal antibodies

Human Ia-like, class II molecules were isolated by immunoprecipitation with monoclonal antibodies from various HLA-D/DR homozygous cell lines and were analyzed by two-dimensional gel electrophoresis. The monoclonal antibody PLM12 reacted with B cells carrying DR4, DR5, DRw6.2, and DRw9 phenotypes, and its reactivity perfectly correlated with the previously defined TB21 (MB3-like) specificity. Class II molecules detected by PLM12 were structurally distinct from those precipitated by the anti-DR monoclonal antibody NC1 on all HLA-DR4, DR5, DRw6.2, and DRw9 homozygous cell lines and showed polymorphism in heavy and light chains among these cell lines. The monoclonal antibodies PLM2 and PLM9 only reacted with B cells carrying DR5 and DRw6.2 and also detected a distinct set of class II molecules from those precipitated by NC1 but identical to those of PLM12. Thus, PLM2 and PLM9 serologically detected a new subtypic antigen of the PLM12-reactive class II molecules. Furthermore, the antibody NC1 precipitated two light chains and one heavy chain from HLA-DRw6.2 homozygous cell line EBV-Sh. The result indicated the presence of three sets of class II molecules: two in a DR family and another carrying the polymorphic determinants detected by PLM2, PLM9, and PLM12 in a second family.

Two-dimensional gel analysis of a second family of class II molecules by polymorphic HLA-DR4,5, and w9 monoclonal antibodies

Human Ia-like, class II molecules were isolated by immunoprecipitation with monoclonal antibodies from various HLA-D/DR homozygous cell lines and were analyzed by two-dimensional gel electrophoresis. The monoclonal antibody PLM12 reacted with B cells carrying DR4, DR5, DRw6.2, and DRw9 phenotypes, and its reactivity perfectly correlated with the previously defined TB21 (MB3-like) specificity. Class II molecules detected by PLM12 were structurally distinct from those precipitated by the anti-DR monoclonal antibody NC1 on all HLA-DR4, DR5, DRw6.2, and DRw9 homozygous cell lines and showed polymorphism in heavy and light chains among these cell lines. The monoclonal antibodies PLM2 and PLM9 only reacted with B cells carrying DR5 and DRw6.2 and also detected a distinct set of class II molecules from those precipitated by NC1 but identical to those of PLM12. Thus, PLM2 and PLM9 serologically detected a new subtypic antigen of the PLM12-reactive class II molecules. Furthermore, the antibody NC1 precipitated two light chains and one heavy chain from HLA-DRw6.2 homozygous cell line EBV-Sh. The result indicated the presence of three sets of class II molecules: two in a DR family and another carrying the polymorphic determinants detected by PLM2, PLM9, and PLM12 in a second family.

Molecular identifications of HLA-DR4, MT3, and TB21 antigens on HLA-DR4 homozygous B cell lines

The HLA-DR locus in the human major histocompatibility complex determines a series of polymorphic cell surface antigens; these antigens are composed of two noncovalently associated glycoproteins of 34,000 daltons and 29,000 daltons and are predominantly expressed on B cells, monocytes, and activated T cells (1). To date, 10 HLA-DR specificities have been well characterized by using alloantisera obtained from multiparous women (2). In addition to these DR antigens, two other B cell alloantigen systems (MT and MB) were proposed on the basis of the serologic data (3,4); the MB1 or MT1 specificities are found in association with DR1, DR2, and DRw6, whereas MT2 is associated with DR3, DR5, DRw6, and DRw8; MT3 is associated with DR4, DR7, and DRw9, and MB3 or MT4 is associated with DR4, DR5, and DRw8, respectively (3, 4). We have also described that the TB21 antigen is expressed in association with DR4, DR5, and DRw9 (5). The HLA-DR, MB, MT, or TB antigens are collectively referred to as class II antigens. The number of human class II antigens has been of primary concern because of their similarity to murine Ia antigens and especially because of their close relationship to certain diseases. With the aid of immunochemical means and alloantisera, it has been demonstrated that at least two loci control human class II molecules (6-10). The data presented in this report show the existence of three class II molecules carrying well-known allospecificities, DR4, MT3, and TB21, on HLA-DR4 homozygous cell lines.

Molecular identifications of HLA-DR4, MT3, and TB21 antigens on HLA-DR4 homozygous B cell lines

The HLA-DR locus in the human major histocompatibility complex determines a series of polymorphic cell surface antigens; these antigens are composed of two noncovalently associated glycoproteins of 34,000 daltons and 29,000 daltons and are predominantly expressed on B cells, monocytes, and activated T cells (1). To date, 10 HLA-DR specificities have been well characterized by using alloantisera obtained from multiparous women (2). In addition to these DR antigens, two other B cell alloantigen systems (MT and MB) were proposed on the basis of the serologic data (3,4); the MB1 or MT1 specificities are found in association with DR1, DR2, and DRw6, whereas MT2 is associated with DR3, DR5, DRw6, and DRw8; MT3 is associated with DR4, DR7, and DRw9, and MB3 or MT4 is associated with DR4, DR5, and DRw8, respectively (3, 4). We have also described that the TB21 antigen is expressed in association with DR4, DR5, and DRw9 (5). The HLA-DR, MB, MT, or TB antigens are collectively referred to as class II antigens. The number of human class II antigens has been of primary concern because of their similarity to murine Ia antigens and especially because of their close relationship to certain diseases. With the aid of immunochemical means and alloantisera, it has been demonstrated that at least two loci control human class II molecules (6-10). The data presented in this report show the existence of three class II molecules carrying well-known allospecificities, DR4, MT3, and TB21, on HLA-DR4 homozygous cell lines.

Separation of four class II molecules from DR2 and DRw6 homozygous B lymphoid cell lines

Four human class II molecules, one FA, one DC1, and two DR-like molecules, were isolated from DR2 and DRw6 homozygous cell lines by means of a variety of monoclonal antibodies and were compared with each other by two-dimensional (2-D) gel electrophoresis. Anti-DR2 or anti-DR3 + 5 + w6 sera immunoprecipitated two distinct light chains (L1 and L2) and one heavy chain (H1) from a DR2 or DRw6 homozygous cell line, respectively. One or both of these two class II molecules were also immunoprecipitated by "DR-specific" monoclonal antibodies and were considered to constitute a "DR" family of molecules. Three DC1-specific monoclonal antibodies, SDR4.1, Tu22, and PLM5, immunoprecipitated a set of heavy (H2) and light (L3) chains distinct from those of two DR-like molecules. The heavy chains of the DC1 antigens from DR2 and DRw6 cell lines were indistinguishable, whereas the light chains were structurally distinct from each other. A fourth molecule, FA, was identified by a novel monoclonal antibody and was also detected by two additional antibodies, Tu39 and SG171, that blocked the SB-specific T-cell proliferative response. The FA light chain (L4) was distinct from those of the former three antigens on both cell lines, whereas the FA heavy chain was indistinguishable from the DC1 heavy chain (H2) in this 2-D gel analysis. Thus, four light chains and two heavy chains were isolated from both DR2 and DRw6 homozygous cell lines. A possible gene-antigen organization of the DC-like antigens was also discussed.