Interleukin 2 production by peripheral blood lymphocytes in allograft recipients during acute rejection episodes

Interleukin 2 production by peripheral blood lymphocytes in allograft recipients during acute rejection episodes. Inthis study we investigate the relationship between the Interleukin 2 (IL-2) yield produced by kidney allograft recipient's peripheral blood lymphocytes (PBL) under lectin stimulation and the occurrence of acute rejection episodes. PBL were harvested prospectively before grafting, after grafting in steady-state period, and at the onset of acute rejection episodes. In addition, we tested retrospectively the ability of PBL of recipients engrafted for more than 1yr to produce IL-2. IL-2 levels were assessed on the IL-2-dependent CTL-L2 murine cell line. Our data show: 1) before grafting, hemodialysed patients (N = 14) produced normal IL-2 yield compared with healthy donors (N = 21); 2) the IL-2 secretion of PBL ofrecipients with good graft function (N = 18) is decreased markedly during roughly the first 12 months following transplantation (P < 0.01); 3) when acute rejection crisis occurred during this time period (N = 24), a sharp and highly significant increment (P < 0.01) in lectin-induced IL-2 production of recipient's PBL was seen. After 1 yr, the capacity to secrete IL-2 upon lectin stimulation tends to be restored. Finally, our data correlate rejection and high PBL-IL-2 secretion clearly at a time when recipients with well-functioning grafts have markedly impaired IL-2 secretion

Loss of IL-10 secretion by regulatory B lymphocytes in multiple sclerosis patients

International audienc

Natalizumab alters the TCR repertoire after one year of treatment in four MS patients

International audiencen.

Generation of cattle knockout for galactose‐α1,3‐galactose and N‐glycolylneuraminic acid antigens

Two well-characterized carbohydrate epitopes are absent in humans but present in other mammals. These are galactose-α1,3-galactose (αGal) and N-glycolylneuraminic acid (Neu5Gc) which are introduced by the activities of two enzymes including α(1,3) galactosyltransferase (encoded by the GGTA1 gene) and CMP-Neu5Gc hydroxylase (encoded by the CMAH gene) that are inactive in humans but present in cattle. Hence, bovine-derived products are antigenic in humans who receive bioprosthetic heart valves (BHVs) or those that suffer from red meat syndrome. Using programmable nucleases, we disrupted (knockout, KO) GGTA1 and CMAH genes encoding for the enzymes that catalyse the synthesis of αGal and Neu5Gc, respectively, in both male and female bovine fibroblasts. The KO in clonally selected fibroblasts was detected by polymerase chain reaction (PCR) and confirmed by Sanger sequencing. Selected fibroblasts colonies were used for somatic cell nuclear transfer (SCNT) to produce cloned embryos that were implanted in surrogate recipient heifers. Fifty-three embryos were implanted in 33 recipients heifers; 3 pregnancies were carried to term and delivered 3 live calves. Primary cell cultures were established from the 3 calves and following molecular analyses confirmed the genetic deletions. FACS analysis showed the double-KO phenotype for both antigens confirming the mutated genotypes. Availability of such cattle double-KO model lacking both αGal and Neu5Gc offers a unique opportunity to study the functionality of BHV manufactured with tissues of potentially lower immunogenicity, as well as a possible new clinical approaches to help patients with red meat allergy syndrome due to the presence of these xenoantigens in the diet

Differential Immune Response to Bioprosthetic Heart Valve Tissues in the α1,3Galactosyltransferase-Knockout Mouse Model

Structural valve deterioration (SVD) of bioprosthetic heart valves (BHVs) has great clinical and economic consequences. Notably, immunity against BHVs plays a major role in SVD, especially when implanted in young and middle-aged patients. However, the complex pathogenesis of SVD remains to be fully characterized, and analyses of commercial BHVs in standardized-preclinical settings are needed for further advancement. Here, we studied the immune response to commercial BHV tissue of bovine, porcine, and equine origin after subcutaneous implantation into adult a1,3-galactosyltransferase-knockout (Gal KO) mice. The levels of serum anti-galactose a1,3-galactose (Gal) and -non-Gal IgM and IgG antibodies were determined up to 2 months post-implantation. Based on histological analyses, all BHV tissues studied triggered distinct infiltrating cellular immune responses that related to tissue degeneration. Increased anti-Gal antibody levels were found in serum after ATS 3f and Freedom/Solo implantation but not for Crown or Hancock II grafts. Overall, there were no correlations between cellular-immunity scores and post-implantation antibodies, suggesting these are independent factors differentially affecting the outcome of distinct commercial BHVs. These findings provide further insights into the understanding of SVD immunopathogenesis and highlight the need to evaluate immune responses as a confounding factor