Molecular variation at the HLA-A, B, C, DRB1, DQA1, and DQB1 loci in full heritage American Indians in Arizona: private haplotypes and their evolution

A sample of 492 full heritage, unrelated residents of the Gila River Indian Community (GRIC) of Arizona were characterized for their high-resolution DNA alleles at the HLA-A, B, C, DRB1, DQA1, and DQB1 loci. Only five allelic categories are found at HLA-A, 10 at HLA-B, 8 at HLA-C and HLA-DR, and 4 at DQA1 and DQB1. There is little evidence for population structure at the 6 loci. Two 'private' alleles, B*5102 and B*4005, which are found nearly exclusively in American Indian populations in the desert southwest and northern Mexico, are likely new mutations after the first inhabitation of the area, the evolution of which are reflected in the contemporary distribution of their respective haplotypes. DRB1*1402 has the highest reported frequency of any specificity at the DRB1 locus, 0.7461, and serves as a sensitive probe for locating related east Asian populations. The haplotypes in this population also exhibit a highly restricted distribution and strong genetic disequilibria, which has important implications for matching solid organ and bone marrow allografts. It is shown that, when one considers HLA-A-B-DRB1 homozygotes as allograft donors for all full heritage members of the GRIC, 50% of the community would find a non-mismatched organ within the homozygotes for the six most common haplotypes. This raises questions about transplantation policy and whether, in the presence of high-frequency private alleles and a restricted number of haplotypes, the full heritage American Indian community of the desert southwest should act as its own pool of donors for its affected members.

Measurement of G(E(p))/G(M(p)) in e(-->)p---> e(-->)p to Q(2) = 5.6 GeV(2)

The ratio of the electric and magnetic form factors of the proton G(E(p))/G(M(p)), which is an image of its charge and magnetization distributions, was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the recoil polarization technique. The ratio of the form factors is directly proportional to the ratio of the transverse to longitudinal components of the polarization of the recoil proton in the elastic e(-->)p---> e(-->)p reaction. The new data presented span the range 3.5< Q(2)< 5.6 GeV(2) and are well described by a linear Q(2) fit. Also, the ratio sqrt[Q(2)] F(2(p))/F(1(p)) reaches a constant value above Q(2) = 2 GeV(2).

Epidermal powder immunization induces both cytotoxic T-lymphocyte and antibody responses to protein antigens of influenza and hepatitis B viruses

Cytotoxic T lymphocytes (CTL) play a vital role in host defense against viral and intracellular bacterial infections. However, nonreplicating vaccines administered by intramuscular injection using a syringe and needle elicit predominantly humoral responses and not CTL responses. Here we report that epidermal powder immunization (EPI), a technology that delivers antigens on 1.5- to 2.5-microm gold particles to the epidermis using a needle-free powder delivery system, elicits CTL responses to nonreplicating antigens. Following EPI, a majority of the antigen-coated gold particles were found in the viable epidermis in the histological sections of the target skin. Further studies using transmission electron microscopy revealed the intracellular localization of the gold particles. Many Langerhans cells (LCs) at the vaccination site contained antigen-coated particles, as revealed by two-color immunofluorescence microscopy, and these cells were found in the draining lymph nodes 20 h later. Immune responses to several viral protein antigens after EPI were studied in mice. EPI with hepatitis B surface antigen (HBsAg) and a synthetic peptide of influenza virus nucleoprotein (NP peptide) elicited antigen-specific CTL responses as well as antibody responses. In an in vitro cell depletion experiment, we demonstrated that the CTL activity against HBsAg elicited by EPI was attributed to CD8(+), not CD4(+), T cells. As controls, needle injections of HBsAg or the NP peptide into deeper tissues elicited solely antibody, not CTL, responses. We further demonstrated that EPI with inactivated A/Aichi/68 (H3N2) or A/Sydney/97 (H3N2) influenza virus elicited complete protection against a mouse-adapted A/Aichi/68 virus. In summary, EPI directly delivers protein antigens to the cytosol of the LCs in the skin and elicits both cellular and antibody responses.

Validation of DNA-based HLA-A and HLA-B testing of volunteers for a bone marrow registry through parallel testing with serology

A total of 42,160 individuals were typed for HLA-A and HLA-B by both serology and PCR-based typing. The HLA assignments included all of the known serological equivalents. The majority of the individuals (99.9%) were from U.S. minority population groups. The serologic typing was performed between 1993 and 1997 at the time of recruitment for the National Bone Marrow Program (NMDP) registry. The polymerase chain reaction (PCR)-based typing was carried out in two phases. In phase I, DNA typing was performed by PCR using sequence-specific oligonucleotide probes (PCR-SSOP) or PCR using sequence-specific primers (PCR-SSP) without knowledge of the serologic assignments. Discrepancies were identified between the serologic and DNA assignments in 24% of the volunteers (8% of volunteers differed for only HLA-A assignments, 13% for HLA-B, and 3% for both HLA-A and -B) and a potential explanation was assigned each discrepant serology/DNA pair. In phase II, a random sampling scheme was used to select a statistically significant number of individuals for repeat DNA typing from each of these categories. The categories included antigens missed by serology, nonexpressed (null) alleles, PCR amplification failures, misassignment of antigens and nomenclature issues. Only a single individual was found to carry a null allele. DNA-based testing correctly typed nearly 99% of the donors at HLA-A, more than 98% at HLA-B, and more than 97% at both HLA-A and -B validating this methodology for registry typing.

Large-scale DNA-based typing of HLA-A and HLA-B at low resolution is highly accurate specific and reliable

DNA-based typing of HLA class I alleles of the HLA-A and HLA-B loci using sequence-specific oligonucleotide primers and/or probes has been used for the large-scale typing of individuals for the National Marrow Donor Program unrelated donor registry. Typing was performed by 16 laboratories at a low level of resolution (e.g. A*01, B*07). The results of blinded quality control analysis for the first 12 months of the project show the typing to be highly accurate, specific and reliable. The total error rate based on 11,545 HLA-A and 11,428 HLA-B assignments was 1.1% for HLA-A and 1.9% for HLA-B. This level of accuracy is particularly remarkable because the quality control samples could not be distinguished from 64,180 donor samples tested at the same time by the laboratories.

Fatal granuloma necrosis without exacerbated mycobacterial growth in tumor necrosis factor receptor p55 gene-deficient mice intravenously infected with Mycobacterium avium

The pathogenesis of mycobacterial infections is associated with the formation of granulomas in which both antibacterial protection and tissue damage take place concomitantly. We used murine Mycobacterium avium infection to compare the development of granulomatous lesions in intravenously infected tumor necrosis factor receptor p55 (TNFRp55) gene-deficient (p55(-/-)) mice to the development of granulomatous lesions in M. avium-infected syngeneic C57BL/6 (p55(+/+)) mice. Up to 5 weeks after infection with either the highly virulent M. avium strain TMC724 or the intermediately virulent M. avium strain SE01, bacterial counts in the liver, spleen, and lung of p55(-/-) mice were identical to or lower than those in infected p55(+/+) mice. However, the formation of mononuclear cell foci in the liver was delayed by approximately 2 to 3 weeks in p55(-/-) mice compared to the results obtained for infected p55(+/+) mice. Despite comparable bacterial loads, granulomas in p55(-/-) mice underwent progressive necrosis, causing damage to the surrounding liver tissue. The appearance of necrotizing granulomas was associated with the death of all infected p55(-/-) mice, regardless of the virulence of the M. avium strain used for infection. Granulomatous lesions in the liver contained three times as many CD3(+) cells in p55(-/-) mice yet appeared more diffuse than in p55(+/+) mice. Semiquantitative reverse transcription-PCR studies revealed that prior to mouse death, interleukin-12 (IL-12) and gamma interferon mRNA levels were up regulated in the livers of infected p55(-/-) mice, while mRNA levels for tumor necrosis factor, the inducible isoform of nitric-oxide synthase (iNOS), and IL-10 were similar to those found in infected p55(+/+) mice. In response to persistent mycobacterial infection, the absence of TNFRp55 causes the disregulation of T-cell-macrophage interactions and results in fatal granuloma necrosis even when adequate antibacterial functions are maintained.

The resistance against Listeria monocytogenes and the formation of germinal centers depend on a functional death domain of the 55 kDa tumor necrosis factor receptor

The biological functions mediated by the death domain of the 55-kDa tumor necrosis factor receptor (TNFRp55) in vivo are still elusive. TNFRp55 mutants lacking a functional death domain were expressed in TNFRp55-/- and in TNFRp55+/- mice as transgenes under control of the H-2Kb promoter. Analysis of these animals revealed that signals originating from the TNFRp55 death domain are indispensable for the protection against Listeria monocytogenes, the expression of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in the spleen and the development of splenic germinal centers. Furthermore, the transgenic coexpression of the TNFRp55 mutants in TNFRp55+/- mice exerts a dominant negative effect on the signaling of the endogenous receptor chains in vivo.

Mature follicular dendritic cell networks depend on expression of lymphotoxin beta receptor by radioresistant stromal cells and of lymphotoxin beta and tumor necrosis factor by B cells

The formation of germinal centers (GCs) represents a crucial step in the humoral immune response. Recent studies using gene-targeted mice have revealed that the cytokines tumor necrosis factor (TNF), lymphotoxin (LT) alpha, and LTbeta, as well as their receptors TNF receptor p55 (TNFRp55) and LTbetaR play essential roles in the development of GCs. To establish in which cell types expression of LTbetaR, LTbeta, and TNF is required for GC formation, LTbetaR-/-, LTbeta-/-, TNF-/-, B cell-deficient (BCR-/-), and wild-type mice were used to generate reciprocal or mixed bone marrow (BM) chimeric mice. GCs, herein defined as peanut agglutinin-binding (PNA+) clusters of centroblasts/centrocytes in association with follicular dendritic cell (FDC) networks, were not detectable in LTbetaR-/- hosts after transfer of wild-type BM. In contrast, the GC reaction was restored in LTbeta-/- hosts reconstituted with either wild-type or LTbetaR-/- BM. In BCR-/- recipients reconstituted with compound LTbeta-/-/BCR-/- or TNF-/-/BCR-/- BM grafts, PNA+ cell clusters formed in splenic follicles, but associated FDC networks were strongly reduced or absent. Thus, development of splenic FDC networks depends on expression of LTbeta and TNF by B lymphocytes and LTbetaR by radioresistant stromal cells.

Listeriosis in p47(phox-/-) and TRp55-/- mice: protection despite absence of ROI and susceptibility despite presence of RNI

The significance of host defense mechanisms in primary listeriosis in vivo is incompletely understood. Here, we show that tumor necrosis factor receptor p55-/- (TRp55-/-) mice are susceptible to Listeria monocytogenes infection in the presence of leukocyte recruitment, inflammatory cytokine production (including IFNgamma), nitric oxide synthesis, and oxidative burst formation. Mice deficient for oxidative burst (p47[phox-/-] mice) are relatively resistant to listeriosis. Despite activation of these antibacterial effector systems, TRp55-/- phagocytes in vivo are incapable of confining and eradicating L. monocytogenes inside phagolysosomes. Bone marrow chimeras reveal that for eradication of L. monocytogenes, TRp55 is crucially required only on cells from hematopoietic origin. Unexpectedly, prior to death, exocrine pancreatic cells undergo apoptosis in TRp55-/- mice. Collectively, these data demonstrate that in vivo, TRp55 initiates a protective, listericidal mechanism in phagocytes that differs from nitric oxide production and oxidative burst formation and that uncontrolled listeriosis results in necrotizing pancreatitis in TRp55-/- mice.

The catalytic domain of the cGMP-dependent protein kinase Ialpha modulates the cGMP-binding characteristics of its regulatory domain

The cGMP-dependent protein kinase Ialpha (PKG Ialpha) possesses two functional moieties, the regulatory and catalytic domains, which reside on a single polypeptide chain. Here we report on the influence of the catalytic domain on the binding of cGMP to the regulatory domain. A deletion mutant, delta352-670 of PKG Ialpha, lacking the catalytic domain, was constructed and expressed in E. coli. The purified 38 kDa mutant protein showed strong reactivity toward tryptic proteolysis at residue Arg77. Thus, a double deletion fragment delta1-77/352-670 PKG Ialpha, lacking the N-terminus, was also purified. Both proteins had functional cGMP binding, but differed kinetically from the wild-type protein. First the affinity constants for cGMP were modulated, second the constructs showed no signs of cooperative cGMP binding and third dimerization of the delta352-670 mutant was abolished. Our results provide evidence that the catalytic domain forms an intimate interaction with the regulatory domain and modulates the kinetics of cGMP binding.

Glycerol-induced unraveling of the tight helical conformation of Escherichia coli type 1 fimbriae

Glycerol was found to unravel the helical conformation of Escherichia coli type 1 fimbriae without appreciable depolymerization. The linearized fimbrial polymers have a diameter of 2 nm, react strongly with a monoclonal antibody directed at an inaccessible epitope on native fimbriae, and display greater mannose-binding activity and trypsin sensitivity than native fimbriae. Removal of glycerol by dialysis results in spontaneous reassembly of the linear polymers into structures morphologically, antigenically, and functionally indistinguishable from native fimbriae.

The major histocompatibility complex-restricted antigen receptor on T cells. II. Role of the L3T4 product

We have examined the role of the murine homologue of Leu-3 T4, L3T4, in recognition of antigen in association with products of the major histocompatibility complex (Ag/MHC) by murine T cell hybridomas. A series of ovalbumin (OVA)/I-Ad-specific T cell hybridomas were ranked in their sensitivity to Ag/I by measuring their ability to respond to low doses of OVA, or their sensitivity to inhibition by anti-I-Ad antibodies. T cell hybridomas with low apparent avidity for OVA/I-Ad, i.e. that did not respond well to low concentrations of OVA and were easily inhibited by anti-I-Ad, were also easily inhibited by anti-L3T4 antibodies. The reverse was true for T cell hybridomas with apparent high avidity for Ag/MHC. We found that the presence of low doses of anti-L3T4 antibodies caused T cell hybridomas to respond less well to low doses of Ag, and to be more easily inhibited by anti-I-Ad antibodies. These results suggested that the role of the L3T4 molecule is to increase the overall avidity of the reaction between T cells and Ag-presenting cells. In support of this idea was the discovery of several L3T4- subclones of one of our L3T4+ T cell hybridomas, D0.11.10. The L3T4- subclones had the same amount of receptor for OVA/I-Ad as their L3T4+ parent, as detected by an anti-receptor monoclonal antibody. The L3T4- subclones, however, responded less well to low doses of OVA, and were more easily inhibited by anti-I-Ad antibodies than their L3T4/ parent. These results showed that the L3T4 molecule was not required for surface expression of, or functional activity of, the T cell receptor for Ag/MHC. The L3T4 molecule did, however, increase the sensitivity with which the T cell reacted with Ag/MHC on Ag-presenting cells.