The Journal of Experimental Medicine

Abe, R; Foo-Phillips, M; Hodes, R J

doi: 10.1084/jem.170.4.1059pmid: 2477483

The identity of the self determinants involved in the selection of the T cell repertoire has been a matter of considerable interest. In addition to the apparent critical role of MHC gene products, accumulated experimental results indicate the importance of non-MHC gene products in T cell repertoire selection. In particular, murine Mlsa and Mlsc determinants have been shown to be highly stimulatory to allogeneic T cells and to be involved in the negative selection (elimination) of self-reactive T cells expressing selected TCR V beta segments. In this work, a unique phenomenon of genetic redundancy is described in the control of Mlsc expression: Mlsc appears to be controlled by at least two unlinked loci, and the product of either one of these loci is sufficient to evoke Mlsc-specific T cell response and to act as a ligand in the deletion of self Mlsc-reactive V beta 3+ T cells. Based on these findings, we propose a possible explanation for the fact that Mls-like genes or gene products have not been identified in other species such as man.

Haba, S; Lascombe, M B; Poljak, R J; Nisonoff, A

doi: 10.1084/jem.170.4.1075pmid: 2507724

We have explored the structural basis of idiotopes associated with the major idiotype (CRIA) of A/J anti-p-azobenzenearsonate antibodies, with emphasis on the regions of contact with anti-idiotypic antibody. The analysis was facilitated by a recent description of the three-demensional structure of the Fab portion of a CRIA-related antibody molecule. Direct binding measurements failed to reveal idiotopes associated exclusively with the L chain. However, the L chain participated in the formation of approximately 80% of the idiotopes recognized by polyclonal anti-Id. This indicates that multiple complementarity-determining regions (CDRs) participate in the formation of idiotopes. The affinity of anti-Id for CDRs on L chains must be appreciable but insufficient to permit direct binding (i.e., less than approximately 10(4) M-1). Approximately 20-35% of polyclonal anti-Id reacted with high affinity with H chains recombined with non-CRIA-related L chains. This interaction was found to involve the D region as well as one or both CDRs in the VH segment, again indicating the contribution of multiple CDRs. It is suggested that a typical idiotope may be similar in size to that of protein epitopes whose three-dimensional structures are known; such epitopes comprise a substantial fraction of the surface area occupied by the CDRs of an antibody. The expression of an idiotope recognized by the mAb AD8, which interacts with the VH segment, was found to be unaffected by major changes in the neighboring D and VL regions. This observation is relevant to efforts to predict three-dimensional structure from the amino acid sequence of CRIA+ molecules.

Irwin, M J; Heath, W R; Sherman, L A

doi: 10.1084/jem.170.4.1091pmid: 2477484

As compared with the vigorous T cell response normally observed against allogeneic MHC molecules, T cells recognize xenogeneic MHC molecules poorly. To define structural features of the MHC molecule important for such species-specific recognition, HLA-A2(A2)-specific murine CTL were examined for their recognition of transfected cell lines expressing the class I molecules A2 or A2/H-2Kb(A2/Kb). A2/Kb is a chimeric molecule consisting of the alpha 1 and alpha 2 domains of A2 and the alpha 3, transmembrane, and cytoplasmic regions of Kb. The majority of CTL clones showed enhanced recognition of transfected cell lines expressing this chimeric molecule. Enhanced recognition was shown to correlate with sensitivity of the CTL clones to inhibition by anti-CD8 antibody. These results suggested that CD8 may interact with class I in a species-specific manner, and that suboptimal CD8 interaction with the alpha 3 domain of xenogeneic molecules may be an important contribution to poor xenoreactivity. This conclusion was supported by the capacity of A2/Kb, but not A2 human cell transfectants, to induce a primary in vitro CTL xenoresponse specific for A2.

Ishida, Y; Nishi, M; Taguchi, O; Inaba, K; Hattori, M; Minato, N; Kawaichi, M; Honjo, T

doi: 10.1084/jem.170.4.1103pmid: 2571665

Transgenic mice expressing both human IL-2 and the L chain of IL-2-R constitutively had an unusual expansion of Thy-1+/CD3-4-8- large granular lymphocytes, which bore the elevated NK activity. Unexpectedly, the transgenic mice had neither T cell expansion nor autoreactive antibodies. The increase in number and activity of NK cells seems to be responsible for both the severe interstitial pneumonia and lymphocyte depletion in the spleen that we found in these transgenic mice. In addition, we found the selective loss of Purkinje cells in the cerebellum of the mice, which gave rise to their disturbed gait. All the transgenic mice died by 4 wk of age.

Applegate, L A; Ley, R D; Alcalay, J; Kripke, M L

doi: 10.1084/jem.170.4.1117pmid: 2529340

This study was conducted to explore the involvement of DNA damage in the suppression of contact hypersensitivity (CHS) by UV irradiation. The opossum, Monodelphis domestica, was used because cells of these marsupials have an enzyme that is activated by visible light (photoreactivating enzyme) and repairs ultraviolet radiation (UVR)-induced pyrimidine dimers in DNA. A single dose of 1,500 J/m2 of UVB (280-320 nm) radiation, representing 2 minimal erythema doses, was administered to the dorsal skin of opossums. This treatment prevented the opossums from developing a CHS response to dinitrofluorobenze (DNFB) applied either at the site of irradiation or an unirradiated site. In addition, this dose of UVR decreased the number of ATPase+ epidermal Langerhans cells in the dorsal epidermis to approximately 3% of that in unirradiated skin at the time of DNFB application. Treatment of the animals with wavelengths that activate the repair enzyme (320-500 nm, photoreactivating light, PRL) for 120 min immediately after UV irradiation inhibited the UVR-induced suppression of CHS almost completely. Exposure to PRL before UVR did not prevent UVR-induced suppression of CHS. PRL treatment after UV irradiation also prevented the decrease in the number of ATPase+ Langerhans cells. Measurements of lesions in DNA indicated that PRL treatment removed around 85% of the UVR-induced pyrimidine dimers. These data provide direct evidence that DNA, and most likely, the pyrimidine dimer, is the primary molecular target for the UVB-induced suppression of contact hypersensitivity to haptens applied to irradiated or unexposed skin.

Matsuyama, T; Yamada, A; Kay, J; Yamada, K M; Akiyama, S K; Schlossman, S F; Morimoto, C

doi: 10.1084/jem.170.4.1133pmid: 2477485

In this study, fibronectin synergized with anti-CD3 antibody to promote CD4 cell proliferation in a serum-free culture system. The cell-adhesive domain plus additional regions of the fibronectin molecule are involved in this synergy. Anti4B4(CDw29) antibody blocked the activation of CD4 cells in this system. Furthermore, it is the VLA-5 protein within the set of molecules recognized by anti-4B4 that serves as a fibronectin receptor on the CD4 lymphocytes. The VLA-5 fibronectin receptor was mainly expressed on CD4+ CD45R-CDw29+ cells and may in part contribute to the unique function of these cells.

Collman, R; Hassan, N F; Walker, R; Godfrey, B; Cutilli, J; Hastings, J C; Friedman, H; Douglas, S D; Nathanson, N

doi: 10.1084/jem.170.4.1149pmid: 2571666

To characterize the host range of different strains of HIV-1, we have used four types of cells, primary monocyte-derived macrophages (MDM), primary PBL, a promonocyte cell line (U937), and a CD4+ T cell line (SUP-T1). These cells were infected with three prototype strains of HIV-1, a putative lymphocyte-tropic strain (IIIB), and two putative monocyte-tropic strains (SF162 and DV). Infections were monitored by assays for infectious virus, for cell-free and cell-associated viral antigen (p24), and for the proportion of cells infected by immunohistochemical staining. It was concluded that: (a) the use of four different cell types provides a useful biological matrix for distinguishing the tropism of different strains of HIV-1; this matrix yields more information than the infection of any single cell type. (b) A monocyte-tropic strain of HIV-1, such as strain SF162, shows a reciprocal host range when compared with a lymphocyte-tropic strain such as IIIB; strain SF162 replicates well in primary MDM but not in U937 or SUP-T1 cells, while strain IIIB replicates well in both U937 and SUP-T1 cells but not in MDM. (c) Both lymphocyte-tropic and monocyte-tropic strains of HIV-1 replicate well in PBL. (d) The promonocyte cell line, U937, and the T cell line, SUP-T1, differ markedly from primary cells, such as MDM and PBL, in their ability to support the replication of different strains of HIV-1; these cell lines cannot be used as surrogates for primary cells in host range studies of HIV-1 strains.

Ratcliffe, M J

doi: 10.1084/jem.170.4.1165pmid: 2507725

The avian bursa of Fabricius represents a site for the generation of antibody diversity. Transfer of neonatal bursal cells into cyclophosphamide-treated neonatal chickens results in reconstitution of recipient bursae with donor-derived bursal stem cells. These stem cells express cell surface IgM and, under conditions of limiting donor bursal stem cell numbers, each reconstituted bursal follicle is colonized by a single precursor cell. The expression of an Ig VH idiotype, CVH-1, was found to be heterogenous within such clonal follicles. The diversity generated within the bursa is subsequently found within the peripheral B cell compartment. Thus, the generation of functional Ig H chain diversity is shown to occur subsequent to Ig H chain rearrangement and expression.

Sastry, K; Herman, G A; Day, L; Deignan, E; Bruns, G; Morton, C C; Ezekowitz, R A

doi: 10.1084/jem.170.4.1175pmid: 2477486

The human mannose-binding protein (MBP) plays a role in first line host defense against certain pathogens. It is an acute phase protein that exists in serum as a multimer of a 32-kD subunit. The NH2 terminus is rich in cysteines that mediate interchain disulphide bonds and stabilize the second collagen-like region. This is followed by a short intervening region, and the carbohydrate recognition domain is found in the COOH-terminal region. Analysis of the human MBP gene reveals that the coding region is interrupted by three introns, and all four exons appear to encode a distinct domain of the protein. It appears that the human MBP gene has evolved by recombination of an ancestral nonfibrillar collagen gene with a gene that encodes carbohydrate recognition, and is therefore similar to the human surfactant SP-A gene and the rat MBP gene. The gene for MBP is located on the long arm of chromosome 10 at 10q11.2-q21, a region that is included in the assignment for the gene for multiple endocrine neoplasia type 2A.

Fish, S; Zenowich, E; Fleming, M; Manser, T

doi: 10.1084/jem.170.4.1191pmid: 2477487

To determine how the memory B cell population elicited to one epitope might be used in immune responses to other, structurally related epitopes, we explored the phenomenon of original antigenic sin. Strain A/J mice reproducibly respond to immunization with p-azophenylarsonate (Ars) by production of anti-Ars antibodies encoded predominantly by a single VH gene segment (VHIdCR). The structural analogue of Ars p-azophenylsulfonate (Sulf) fails alone to elicit such V regions, but can do so in A/J mice previously immunized with Ars, providing a means to specifically examine B cells capable of responding secondarily to a crossreactive antigen (i.e., memory cells). VHIdCR-expressing hybridomas were derived from the Ars-primed, Sulf-boosted original antigenic sin response of A/J mice at various times after Ars priming, and the properties of the antibodies they express and the structure of the genes encoding these antibodies were characterized. The data obtained support the following conclusions: (a) The Ars-induced memory B cell population capable of being crossreactively stimulated by Sulf is largely formed from a small fraction of all B cells participating in the anti-Ars primary response that express somatically mutated V regions; (b) the antibody repertoire and clonal composition of this population are stable over long periods of time; (c) memory B cells are capable of clonal expansion in the absence of a high rate of V gene somatic mutation; (d) the activation requirements for clonal selection of memory, versus naive B cells appear to differ; and (e) a major fraction of Ars-induced memory B cells express either IgM or IgG3 prior to and during the initial stages of the sin response.