Rat monoclonal antibodies were produced against the C-terminus of Epstein-Barr virus nuclear antigens 2A (EBNA2A) and 2B (EBNA2B) expressed as bacterial trpE fusion proteins. The initial screening was performed using a soluble bacterial extract containing the fusion proteins. Positive hybridomas were confirmed by immunofluorescence on SF158 (Spodoptera frugiperda) insect cells infected with recombinant baculovirus (Autographa californica nuclear polyhedrosis virus) and expressing the complete EBNA2A or EBNA2B genes. We selected a panel of antibodies which reacted either with both antigens or specifically with EBNA2A or with EBNA2B. The antibodies were extensively characterized using immunoprecipitation, Western blotting, epitope mapping on synthesized peptide segments of EBNA2A, immunocytology, and immunohistology on both cryostat sections and paraffin sections of AIDS-associated primary central nervous system lymphomas.

Direct in vivo labeling of erythrocytes with biotin is shown as a method for estimation of red cell survival as well as of enrichment of young or aged erythrocytes. Two succinimide esters (biotin-N-hydroxysuccinimide ester [BNHS], caproylamidobiotin-N-hydroxysuccinimide ester [C-BNHS] were used for biotin labeling of erythrocytes. With improved syntheses, pure BNHS (mp, 212 degrees-214 degrees C) and the spacered intermediate for C-BNHS, 6-(biotinylamide) hexanoate (mp, 225 degrees-226 degrees C) were obtained in an overall yield of 86%; the yield of C-BNHS (mp, 167 degrees-169 degrees C) was 68%. When three doses of 1 mg C-BNHS are injected intravenously into mice at 24-h intervals, all the red cells are biotin labeled. The rate of red cell production as well as the life span of red cells can be measured without any effect on erythropoiesis or damage by red cells in vitro. The survival curve seems to be linear, with 2.5%-3.3% disappearance of biotin-labeled red cells daily. In mice, in vivo biotin labeling avoids damaging red cells by in vitro procedures and does not influence the steady state of erythropoiesis by hypertransfusion. Therefore, in vivo biotin labeling is a very useful method for determining red cell survival time in small animals.

SUMMARY Bone marrow biopsies from 3229 patients with lymphoproliferative disorders and 1156 patients with benign or reactive lymphoproliferations were investigated and criteria for distinguishing between them are given. Bone marrow involvement was found in 89% of multiple 'myeloma, 64% of non-Hodgkin's lymphomas and 8% of Hodgkin's disease. According to the predominant proliferative cell type there were five major entities in multiple myeloma and non-Hodgkin's lymphomas: (1) plasmacytic; (2) lymphocytic; (3) hairy cell; (4) immunocytic; (5) centrocytic. These were further classified into distinct subtypes each of which had independent prognostic significance. The mode of spread of the lymphoproliferative disorders in the bone marrow showed one of six architectural patterns, which together with the quantity of infiltration in the biopsy (reflecting the tumour cell burden) had significant predictive value. These results demonstrate the value of bone marrow biopsies in the identification, classification and staging of lymphoproliferative disorders, as well as in monitoring the course of disease and the response to therapy.

While afi T cells in mammals may express one of many variable (V) gene families in the 13 had greater than normal numbers of Vp2' T cells and appeared as healthy as thymectomized and untreated controls. While production of IgM and IgG antibodies was unimpaired, IgA antibody production was severely compromised in the Vpldepleted birds. The levels of secretory IgA in bile and lung lavage fluid were reduced 1000-to 10,000-fold and secretory IgA antibodies were not produced in response to mucosal immunization. B-cell production of IgA antibodies thus appears to require T cells expressing the Vp1 genes, whereas T cells that express the Vp2 genes lack this capacity.Most of the T cells in mammals express an antigen receptor composed of a and , f chains, while the others express a T-cell receptor (TCR) composed of 'y and 8 subunits (1). Avian homologues of the mammalian a/3 and y5 TCRs can be identified with monoclonal antibodies. The chicken ySTCR is identified with the TCR1 antibody (2) and two types of af3TCR are identified in gallinaceous birds with the TCR2 and TCR3 antibodies (3)(4)(5). The key to this unexpected finding is provided by the recent cloning of genes in the chicken TCR X3 locus. This P locus contains two variable (V) gene families, one diversity (D) gene, four joining (J) genes, and a single constant region (C) gene (6). Chicken a3 T cells therefore may express either V91 or V,2 genes, the products of which can be recognized, respectively, by the TCR2 and TCR3 antibodies (7). While there is little sequence homology (30%) between the Vp1 and Vp2 genes, members within the two families are very similar (>95% homology). Thus, to an even greater extent than in mammals, which have many Va gene families (1), TCR(3 diversity in birds is generated primarily by junctional variations created by V-D-Jp splicing and insertion of nonencoded nucleotides (6). Interestingly, the numerous Va genes in mammals can be assigned to two superfamilies on the basis of invariant sequences (8): V91 superfamily gene members encode an arginine at position 64 and aspartic acid at position 86 to form a salt bridge between these residues, while V,2 genes instead feature an invariant codon for tyrosine at position 65. These features are retained in the chicken V91 and Vp2 genes, respectively (6).The chicken therefore provides a relatively simple model for study of the functional roles of acB T cells by using the two prototype Va genes. In earlier studies, we found that development ofthe TCR2 thymocyte population can be selectively inhibited by embryonic administration of the TCR2 (V,81 specific) monoclonal antibody (9, 10). When this antibody treatment is combined with surgical removal of the thymus after hatching, sustained suppression of the TCR2 cell population can be achieved in young birds. In the present study, we confirmed the selective suppression of TCR2' cells and observed a profound effect of this treatment on the integrity of mucosal immunity. MATERIALS AND METHODSChickens. Chickens hatched from fertile outbred Wh...