Duck lymphoblasts generated by phytohaemagglutinin (PHA) did not respond to recombinant or Jurkat cell line human interleukin (IL)-2 or possess surface antigens resembling mammalian IL-2 receptors or IL-1 beta. Supernatant fluids from normal and PHA-stimulated duck lymphocyte cultures, and normal and lipopolysaccharide (LPS)-stimulated monocytes, gave negative results in a range of assays for biological activity and immunochemical presence of factors resembling mammalian IL-1 and IL-2. However, supernatant fluids from LPS-stimulated duck monocytes contained IL-6-like activity (up to 35 units/mL) assessed on the 7TD-1 murine cell line. We were unable to demonstrate mRNA that would hybridize to cDNA probes for human IL-1 beta, IL-6, and tumour necrosis factor (TNF) in extracts of blood and lymphoid organs from normal and antigen-stimulated ducks. Because homologous serum or plasma is essential for duck lymphocytes and macrophages to respond to mitogens in vitro, we asked whether this growth-factor-like activity might be caused by substances resembling mammalian cytokines. Serum and plasma were examined for activity consistent with IL-1 and IL-6 on mammalian target cells. None was detected. Instead, both serum and plasma contained inhibitors of human IL-1 beta and IL-6, detected at dilutions up to 1:100. Inhibition by serum was heat (56 degrees C, 30 min) labile but inhibition by plasma was heat stable. The identities and biological functions of these inhibitors remain to be defined.

Animals↗

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cDNA sequence and organization of the immunoglobulin light chain gene of the duck, Anas platyrhynchos.

A cDNA was cloned which encoded an immunoglobulin (Ig) light (L) chain of the White Pekin duck. The organization of the variable (V) and constant (C) domains was analyzed by genomic Southern blotting. The duck L chain gene has a similar chromosomal organization to that of the chicken, with a single lambda-like C region and multiple VL, hybridizing elements. The amino acid sequence of the VL region of the White Pekin duck L chain showed 88% identity with the Muscovy duck and 87% identity with the chicken, the JL region showed 92% identity with these species, and the CL region showed 88% identity with Muscovy duck and 66% with chicken. The constraints imposed by the gene-conversion mechanism of generating antibody diversity might account for the similarities of the avian V region sequences.

Amino Acid Sequence↗

PubMedDate not supplied

Duck immune responses to Riemerella anatipestifer vaccines.

Riemerella anatipestifer (Ra) infection is probably the most economically important infectious disease of farm ducks worldwide but the immune responses to natural infection and vaccines are poorly understood. We have used the lymphocyte transformation test (LTT) to study the expression of cell-mediated immunity (CMI), and the enzyme-linked immunosorbent assay to monitor antibody (Ab) production following administration of formalin-inactivated and live attenuated serotype 2 (= G) Ra vaccines. Lymphocytes (8x10(5) in 200 microl of RPMI + 10% duck serum, in 96 well trays) were stimulated with Ra antigen, prepared by freeze-thaw and sonication; optimum responses were obtained with antigen at 6.25 microg/ml. Cells were cultured for 3 days at 41.6 degrees C/5% CO(2), prior to assessing 3H-thymidine uptake. Ra bacterin, incorporating aluminium hydroxide as adjuvant, stimulated strong but transient (about 4 weeks) LTT response; there was some cross-reaction of the LTT to proteins derived from other serotypes of Ra. Revaccination stimulated slightly stronger responses with the same time course. The Ab response to each vaccination was longer-lived than the LTT response. Vaccination with a live, attenuated strain of Ra stimulated weaker but longer lasting LTT responses, but similar Ab responses compared to the bacterin. It is apparent, therefore, that the transient protection reported using Ra bacterins is due to the fact that the CMI response to these vaccines is transient; and that it is possible for ducks to have detectable levels of serum Ab at times when CMI is not detectable by LTT. These observations are important in terms of our understanding of immunopathogenesis, immunoprophylaxis, and immunodiagnosis in Ra.

Aluminum Hydroxide↗

PubMedDate not supplied

Novel HLA-DR2-related haplotypes in Hong Kong Chinese implicate the DQB1*0602 allele in susceptibility to multiple sclerosis.

Multiple sclerosis (MS) is strongly associated with the HLA-Dw2 haplotype DRw15.DQw6 in Caucasoids, although the relative contributions of DR and DQ loci to disease susceptibility are unknown. The situation is further complicated by the apparent lack of an association between DR2 and MS in Orientals. This study examined 42 DR2-positive chromosomes in healthy Chinese and 12 DR2-positive chromosomes in MS patients from Hong Kong, using oligonucleotide hybridizations of DQA1, DQB1, DRB1, and DRB5 polymerase chain reaction (PCR) products. There was marked heterogeneity in DR2-related haplotypes in controls (ten types), where the most frequent haplotype, confirmed in one family, involved the novel arrangement DRB1*1501, DQB1*0601. Another common haplotype had the unusual combination of DRB1*1602, DRB5*0101 as confirmed by DNA sequencing of the DRB5 allele. In contrast, the most common DR2-related haplotype in MS patients was the 'classical' Dw2 haplotype DRB1*1501, DQB1*0602, with a frequency of 50% compared with 12% in controls (P = 0.01). Novel DR,DQ linkage disequilibrium relationship in Hong Kong Chinese have permitted recognition of DQB1*0602 as a susceptibility allele in DR2-positive MS patients, although a role for the DRB1*1501 allele in MS pathogenesis has not been excluded by this study.

Alleles↗

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Rous sarcoma regression in chickens resistant or susceptible to Marek's disease.

In 4 experiments, strains of chickens relatively susceptible (S-strain, P-line) or resistant (N-line, PDRC) to Marek's disease (MD) were challenged with Rous sarcoma virus (RSV) at 6-8 weeks old. RSV tumors occurred in 94-100% of the birds in each strain, but the number with tumors that regressed during the 40-46-day experiment varied from 7% (S-strain) to 91% (PDRC). The N-line and P-line birds, derived from a random-bred flock with selection only for susceptibility or resistance to MD, regressed their tumors at about equal rates (respectively 59 and 65%). Thus, although the genetic strains differed in ability to regress RSV tumors, the difference was not necessarily related to genetic resistance or susceptibility to MD. Other birds in 2 of the experiments, infected 2-4 weeks earlier with JM or GA isolants of MD virus, had significantly (P less than 0.01) lower incidence of RSV tumor regression than did controls provided that they developed gross lesions of MD.

Animals↗

PubMedDate not supplied

Distribution and co-occurrence of MHC class I, II, and III markers in southern Chinese: implications for autoimmune disease.

A study of MHC class I, II, and III markers in a group of southern Chinese in Hong Kong is reported. HLA antigen frequencies and complement allele frequencies are given, together with statistically significant pair-wise co-occurrences. Over half of the statistically significant positive and negative linkage disequilibria relate to two extended haplotypes. These haplotypes, or components of them, are associated with a number of diseases in Chinese, particularly diseases of autoimmune origin. One haplotype, A2, Bw46, DRw9, appears to be an analogue of the haplotype A1, B8, DR3 which predisposes to similar diseases in Caucasians. The question is raised of why susceptibility to the same group of diseases in two different racial groups should be related to the haplotypes having the strongest linkage disequilibria within those racial groups.

Asian People↗

PubMedDate not supplied

Vaccination response of parentally immune chicks after yolk-sac inoculation of the embryo with inactivated Newcastle Disease Virus.

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Animals↗