Experimental observation of a fundamental length scale of waves in random media.

Waves propagating through a weakly scattering random medium show a pronounced branching of the flow accompanied by the formation of freak waves, i.e., extremely intense waves. Theory predicts that this strong fluctuation regime is accompanied by its own fundamental length scale of transport in random media, parametrically different from the mean free path or the localization length. We show numerically how the scintillation index can be used to assess the scaling behavior of the branching length. We report the experimental observation of this scaling using microwave transport experiments in quasi-two-dimensional resonators with randomly distributed weak scatterers. Remarkably, the scaling range extends much further than expected from random caustics statistics.

Use of fluorescein conjugated staphylococcal protein-A as a labeling agent for porcine lymphocytes.

Staphylococcal Protein-A conjugated to fluorescein (FPA) was compared to a fluorescein conjugated sheep immunoglobulin anti-pig IgG (FSAPG) as a labeling agent for surface IgG positive (sIg+) porcine lymphoid cells. At plateau concentration of the reagents, more lymphoid cells were labeled with FPA than with FSAPG. However, on a protein concentration basis, FPA was less sensitive than FSAPG. As a control, FPA proved to be a poor labeling agent for sIg+ bovine lymphoid cells when compared to FITC conjugated rabbit IgG anti-bovine IgG (FRABG). Adsorptions of porcine lymphoid cells onto Protein-A Sepharose were performed in order to study the differential specificity of the Protein-A for sIg and for free immunoglobulins. The results of such absorptions showed that Protein-A Sepharose, whatever its affinity for Fab fragments from porcine immunoglobulins, could be used to enrich the sIg negative lymphoid cell populations in the pig.

Heat sensitivity of porcine IgG.

The sensitivity to heat of porcine IgG was studied. The serum from immunized pigs was heated at 56 degrees C for 30 min as for decomplementation. The elution pattern of the serum proteins on an agarose gel column showed a dramatic change with the appearance of a large peak of the gel-excluded material. This peak contained mainly IgG molecules which still retained its antibody activity. This fact points to misinterpretations which can easily occur in 7S and 19S antibody recognition during the porcine immune response. Correlation is suggested of this property with the large number of interheavy chain disulfide bridges present in porcine IgG.

Partial inhibition of the humoral immune response of pigs after early postnatal immunization.

The ability of young pigs to be immunized during the postnatal period was studied. Eight groups of pigs born on the same day from 3 sows were injected with hen egg-white lysozyme in Freund's incomplete adjuvant at days 0, 1, 2, 3, 4, 5, 7, and 10 after birth. The serum antibody titers were determined each week. Results indicated that pigs injected within the first 3 days of life exhibited a delay of 10 days in the appearance of the humoral antibodies, compared with the antibody response observed in pigs injected later. Serum antibody titers were markedly lower in the early immunized pigs. The secondary immune response was similar in all pigs. This partial inhibition is not directly linked to the corticoids present in the serum at the immunization day. Possible reasons for this impairment of the humoral immune response were reviewed.

[Adjuvant effect of Quil-A on the porcine humoral immune response (author's transl)]. / Etude de l'effet adjuvant du Quil-A sur la réponse immunitaire humorale chez le porc.

Quil-A, a purified extract of saponin, was analyzed for its adjuvant properties in the porcine humoral immune response against lysozyme. The adjuvant properties of Quil-A are comparable to the oil adjuvant properties in the pig. The optimal dose was found to be 1 mg per pig. Quil-A enhanced also slightly the homocytotropic antibodies.

Immune response gene(s) controlling the humoral antilysozyme response (Ir-Lys) linked to the major histocompatibility complexSL-A in the pig.

A genetic control of humoral immune response in pigs against hen egg-white lysozyme was shown to be linked to the major histocompatibility complexSLA. This control was detected when high antigen doses were used for immunization. It was more prominent with small immunizing doses of lysozyme. Under these latter conditions,SL- A heterozygous individuals exhibited a higher response than correspondingSL- A homozygous animals, suggesting a complementation phenomenon between several genes, at least one of which is linked to the porcine MHC,SL- A.

Transplantation in miniature swine. XII. N-terminal sequences of class I histocompatibility antigens (SLA) and beta 2-microglobulin.

Purified class I histocompatibility antigens (SLA) from three haplotypes were prepared by papain treatment of lymphoid cell membranes obtained from spleens and lymph nodes of miniature swine homozygous at their major histocompatibility complex. Antigens were purified by ion-exchange chromatography followed by gel filtration. Purity was analyzed by SDS-PAGE, and antigenic specificity by inhibition of complement-dependent, alloantiserum-mediated cytotoxicity. The SLA antigens were reduced and alkylated, and the component heavy and light chains were isolated by gel filtration under dissociating conditions. N-terminal amino acid sequences were obtained for SLAaa, SLAcc, and SLAdd heavy chains, as well as for the light chain, beta 2-microglobulin. The swine antigens showed high levels of homology with class I antigens from other animal species. Heterogeneity was observed among the swine haplotypes, and several of the positions at which substitutions were found are apparently invariant in other animal species. In contrast, only minimal sequence heterogeneity was detected within haplotypes, the basis of which may be of relevance to understanding the evolutionary development of these molecules.

Influence of birth prematurity on colostrum composition and subsequent immunity of piglets.

Two groups of seven pregnant sows were farrowing either naturally after 111-114 days of gestation or prematurely after 109 days following an injection of 125 micrograms/animal of a prostaglandin analogue. Colostrum intake was controlled individually on piglets during the first 24 h of life. Measurements of IgG, IgA and IgM were performed on 3 samples of colostrum after 0, 12 and 24 h following the birth of the first piglet, then in the serum of the piglets, sampled at 4, 12 and 42 days of age. Then, we calculated the total amount of Ig intake during the first 24 h of life and an estimation of the Ig stores of each piglet on the basis of weight, blood volume, and hematocrit at different ages. Results showed a marked average difference in the birth weight in favour of mature piglets as well as an increased colostrum intake: 315 vs an average of 213 g for premature piglets. Considerable variations between sows were found in the initial level of colostral IgG, independently of the gestation length. Two thirds of the IgG intake by piglets occurred during the first 12 h. Total Immunoglobulin intake in the first day was respectively 15.8 g vs 25.1 g for premature or mature piglets. Total estimated Ig content in the serum of 4 day-old piglets was also lower for premature ones (2.55 vs 3.2 g/animal), representing 10 to 27% of the total amount of Igs ingested during the first day of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Transplantation in miniature swine. IX. Swine histocompatibility antigens: isolation and purification of papain-solubilized SLA antigens.

Histocompatibility antigens have been purified by papain treatment of crude cellular membranes obtained from spleen and mesenteric lymph nodes of individual miniature swine that are homozygous at the major histocompatibility complex. The purification protocol included ultracentrifugation, gel filtration, ion-exchange chromatography, and in some instances preparative isoelectric focusing. This procedure was applied to the preparation of sLA antigens from the 3 haplotypes available in our partially inbred miniature swine herd. The purity of the SLAdd molecules was evidenced by: 1) a single activity peak of approximately 50,000 daltons on gel-permeation chromatography; 2) the antigen elution as a symmetrical peak from ion-exchange resins and from isoelectric focusing columns; 3) the presence of 2 predominant polypeptide chains on SDS-PAGE at apparent m.w. 43,000 and 13,000 daltons; and 4) specific immunoprecipitations by alloantisera and by anti-beta 1 microglobulin antisera. The antigenic activity of SLA products was analyzed by inhibition of complement-mediated cytotoxicity and by removal on anti-beta 2-microglobulin affinity columns. Heavy and light chains were separated by gel-filtration on Sephacryl S-200 in 6 molar guanidine. These SLA products, which have thus been shown to be pure by a variety of criteria, are now readily available for structural analysis and for analysis of biologic activity.

Recognition of HLA class I molecules by antisera directed to synthetic peptides corresponding to different regions of the HLA-B7 heavy chain.

Antisera have been prepared in rabbits and in mice against different peptides corresponding to four hydrophilic and variable regions of HLA-B7 heavy chain (65-82, 99-118, 138-157, and 164-187). Specific antipeptide sera have been obtained with all synthetic peptides; for three of them which were more than 20 amino acids long, highly potent sera were elicited by injection of the free peptide. Three overlapping peptides included in region 138-157 have been used, and two different antigenic sites were detected in this region. HLA molecules solubilized in nonionic detergent were precipitated by antipeptide sera directed against regions 65-82, 138-157, and 164-187, but not by antipeptide serum directed against the less hydrophilic region 99-118. Analysis by two-dimensional electrophoresis of the isolated molecules confirmed the anti-HLA specificity of the antipeptide 65-82 and 138-157 sera. Variable numbers of HLA-related spots were found according to the antisera used. Antipeptide 138-157 serum precipitated numerous HLA molecules and therefore probably reacted with monomorphic determinants whereas antipeptide 65-82 appeared specific for a more limited number of HLA antigens. Such reagents directed against well-defined regions of the HLA class I heavy chain are of considerable interest, notably for the mapping of antigenic epitopes on the molecule and for the study of relationships between structure and function.

Serological expression after sequential double transfection with purified HLA-A11 gene of mouse fibroblasts carrying human beta-2 microglobulin.

A genomic cosmid library constructed from DNA from a genotyped individual (JF = HLA-A11, Cw-, B38/A26, Cw7, B51) was screened for clones containing class I histocompatibility genes. Among these clones, one was found to carry a 4.8 kb Hind III fragment which is highly correlated with HLA-A11. This clone was used to transfect LMTK+ cultured mouse fibroblast transformants expressing human beta-2 microglobulin. The human beta-2 microglobulin heavy chain-associated determinant was positively detected by the M18 monoclonal antibody. HLA-A11 expression on these doubly transformed cells was specifically demonstrated by complement-dependent cytotoxicity with HLA-A11 + A3-specific but not with HLA-A3-specific monoclonal antibodies. Absorption studies with human alloantisera confirmed the presence on these cells of HLA-A11 determinants and of cross-reacting determinants which absorbed anti-HLA-A1 and -A3 alloantisera. The JF5-J27 transfected cell expressed both heavy and light chains of human class I histocompatibility genes.