Genetic improvement in sows' prolificity is limited by their milk capacities, which do not allow all piglets to survive or grow normally. This experiment compared the behaviour, growth and immune responses of piglets that were weaned early at 6 days of age (EW) vs. control Large White piglets' (C) suckled by their mothers. Behaviour of 9 litters of 5 to 8 piglets in each group were observed from d5 to d20. All piglets were weighed from birth to d74. Three piglets from each group were slaughtered on d36 for immunological analysis. Until they began to eat dry food, EW piglets walked and vocalised more than C piglets. After that time, when resting, they were less often lying down and more frequently in contact with littermates under the heater. Aggressive behaviour and belly-nosing were more frequent. They displayed a more marked growth check after weaning than did C piglets until 28 days of age. In EW piglets, at 36 days of age, there was a higher density of T- and B-lymphocytes in the gut epithelium and lamina propria, fespectively, in relation to the size of lymphoid follicles of Peyer's patches. The results indicate great behavioural adaptation capacities of very early-weaned piglets, together with earlier maturation of their gut immune system.

Adaptation, Physiological↗

PubMedDate not supplied

Specificity of pig T lymphocyte antiserum: cytotoxicity and inhibiting properties onto E-rosette-forming lymphocytes.

The immunoglobulins obtained from a sheep anti-pig thymocyte serum were made specific for a subpopulation of porcine lymphocytes by adsorptions with pig red blood cells and bone marrow cells. In the presence of rabbit complement, these immunoglobulins killed a porcine lymphocyte subpopulation similar to the subpopulation of lymphocytes forming rosettes with sheep red blood cell (E-rosettes) when enhanced by dextran. Without complement, these immunoglobulins inhibited the E-rosette phenomenon at a dilution near to the cytotoxicity titre of the serum, but did not inhibit the rosettes formed with activated zymosan (ZC rosettes). These two different tests revealed the presence of antibodies directed against pig T-lymphocyte specific antigens and allowed the quantitication of T lymphocytes in different organs.

Animals↗

PubMedDate not supplied

[Heterophile haemagglutinogens on pig, canine and human thymocytes (author's transl)].

Immunization of sheep or horse with pig, canin or horse thymocytes produces heteroagglutinating antibodies, which allow to define two heterophile antigens:--the first one, HC, immunogen for sheep, is localized on pig, human and canin thymocytes, as well as on red blood cells of the two latter species;--the other, HCP, immunogen for horses, is situated on the red blood cells and thymocytes of the same three species. HC is distributed on various cells and in similar fashion in pig and human, except for the pig red blood cells.

Agglutinins↗

PubMedDate not supplied

Specific cytotoxic lymphocyte response in swine against structural proteins of transmissible gastro-enteritis virus: a study using lymphoblastoid cell line and recombinant vaccinia virus.

To determine the specificity, if any, of cellular cytotoxicity against transmissible gastro-enteritis virus (TGEV) infected cells, we developed a test using B lymphoblasts from a MHC histocompatible (d/d haplotype) cell line (L14), as stimulating and target cells. These cells were previously infected with recombinant vaccinia virus including different TGEV structural genes, either the spike (vS), membrane (vM) or nucleoprotein gene (vN). Lymphocytes from a TGEV immunized (d/d) swine developed a cytotoxic activity after secondary in vitro stimulation in the presence of vS, vM or vN infected L14 cells. The cytotoxic activity was induced and directed against the homologous vS and vM infected cells but no cytotoxic activity occurred at all against vN infected cells. While vM infected cells induced a cytotoxic activity against vM infected cells only, vS infected cells stimulated a cross-reactive cytotoxic activity against vM and vN infected cells in addition to that against vS infected cells. This latter cytotoxicity may be due to an increase in a non-specific background of Natural Killer or lymphocyte activated killer activity, which is seen also after coculture with wild type vaccinia virus (vW) infected cells. Thus these results are of practical importance in two respects. First, lymphoïd B cell lines represent an excellent tool for determining which viral antigens are recognized by cytotoxic lymphocytes and second, they indicate the need to incorporate the M and S genes into a TGEV vaccine to induce cellular immunity against TGEV.

Animals↗