PubMed Health⌕ Search

Biomedical subjects

P Richiardi

Publications and source records attributed to P Richiardi.

11 recordsLinked to original sources
PubMed1979

Xenoantisera to allotypic specificities of HLA-A and B antigens. Serological characterization.

By using the lysostrip and the blocking of cytotoxicity by Fab2 fragments, HLA-A and B antibodies were detected in sera from rabbits and goats immunized with human high-density lipoprotein (HDL)-associated HLA antigens isolated from sera and from cultured lymphoid cells. After appropriate absorptions, the xenoantisera became specific for HLA-A and B alloantigens, reacted with the same structures as alloantisera, and displayed the same patterns of cross-reactions as alloantisera; however, several xenoantisera contained antibodies cross-reactive with antigens coded by the A and B loci. Our data indicate that HDL-associated HLA antigens isolated from lymphoid cells and from serum efficiently elicit xenoantibodies to allotypic specificities of the human histocompatibility system.

Animals↗
PubMed1979

Two HLA-D and DR alleles are associated with coeliac disease.

A group of 45 children affected with Coeliac Disease (CD) was typed for HLA-A, B, C, D, and DR specificities. The most significant associations were found with two alleles of the D series, with both cellular and serological typing. It is suggested that the susceptibility to CD is determined by two different genes within the HLA region, the first in common with organ-specific autoimmune diseases and associated with DW3, the second possibly specific for CD and associated with Dw7.

Adolescent↗
PubMed1979

Sera from volunteers immunized by planned blood transfusions as source of DR cytotoxic typing reagents.

Sera from volunteers immunized with planned blood transfusions were tested for anti DR cytotoxic antibodies with a panel of HLA typed cultured human lymphoid cells using a variety of serological techniques. The majority of sera contained DR cytotoxic antibodies. The specificity of DR antibodies in seven sera was determined by testing them with a panel of B peripheral lymphocytes typed with DR alloantisera submitted to the 7th International Histocompatibility Workshop. The temporal evolution of DR and HLA-A and B cytotoxic antibodies was determined in two subjects by testing serial bleedings with B lymphoid cells, coated with Fab2 fragments from anti beta 2 mu and anti DR xenoantisera. Results indicated a parallel evolution of DR and HLA-A and B cytotoxic antibodies.

Antibody Specificity↗
PubMed1978

Appearance and evolution of anti-Da (B cell-specific) antibodies after planned immunizations.

Appearance and evolution of anti-Da antibodies has been followed in eight volunteers immunized by whole blood transfusions or leukocyte intradermal injections form a single donor incompatible for HLA--A,--B,--C and--D specificities. Several unabsorbed bleedings from each recipient were studied against the specific immunizer with three different complement-dependent lymphocytotoxicity (CdL) techniques: (1) standard NIH CdL on total peripheral blood lymphocytes (PBL); (2) VII Workshop standard CdL technique on B cell-enriched suspensions; (3) beta2 microglobulin blanketing test ("bb" test) on B cells. Results obtained with the "bb" test were confirmed with platelet-absorbed sera. The "bb" and the absorbed sera allow discrimination between anti-Da and anti-HLA--A,--B,--C antibodies. Stage of appearance and evolution are rather similar for an anti-HLA--A,--B,--C and anti-Da. An early appearance of antibodies positive only against B cells is due to weak anti-HLA--A,--B antibodies which react better with B cells than with total PBL. Immunogenicity of Da antigens seems to be of the same order as HLA--A, and--B. In fact, Da reactivity was present in all eight recipients studied. These reactivities always segregated in familes with these HLA haplotypes. On a small panel of unrelated D-typed donors, three sera showed a significant positive association with D alleles.

Antibody Specificity↗
PubMed1978

Subdivisions of the HLA-B5 and Bw35 complex.

Population studies in 579 individuals, previously phenotyped to be B5 or Bw35, were carried out with 23 HLA antisera defining the B5-Bw35 complex. The inheritance of five subdivisions in this complex, B5.1, B5.2, B5.y, Bw35 and BHR were tested in 23 families. Differing frequencies of these specificities were observed in American Indians, Blacks, Caucasians, Chinese, Filipinos, Japanese and Mexican Americans.

Epitopes↗
PubMed1977

HLA antibodies cytotoxic only for B lymphocytes.

Of 28 unabsorbed sera from polytransfused individuals or multiparous women, which were not cytotoxic for total peripheral blood lymphocytes, 13 were found to react positively against B cell-enriched suspensions. These 13 sera were further characterized after platelet absorption-elution, as well as by pretreatment with turkey anti-human-beta2-microglobulin serum. Different patterns were found: five sera behaved as pure anti-B cell reagents; four seemed to contain different antibody populations, directed against both B cell determinants and HLA-A, -B or -C antigens; four only contained antibodies directed against HLA-A, -B or -C specificities. Absorption experiments with purified T and B lymphocytes, showed that these last sera, although noncytotoxic for T cells, can be absorbed by them. It was concluded that not all sera reacting only with B lymphocytes recognize specifities absent from T cells, and that all sera should be exhaustively absorbed with platelets before being tested as anti-B cell-specific reagents.

Absorption↗
PubMed1975

Antigenic determinants of the W28 molecule different from but spatially close to W28 determinant.

The existence of two allelic determinants, subtypic to W28 (named TO54 and TO55), and of an antibody cross-reacting W28 times HL-A10, is demonstrated. These new determinants have been studied by means of population and family studies and with the following serological techniques: absorption, elution, lysostrip and blocking by F(ab)-2 fragment. The results suggest that determinants TO54 and TO55 are very similar each other and are spatially close to the supertypic factor.

Adsorption↗