Biomedical subjects

A K Lascelles

Publications and source records attributed to A K Lascelles.

At least 37 records · Page 2Linked to original sources

PubMed1975

The effect of pre-partum milking on the transfer of immunoglobulin into mammary secretion of cows.

The significance of local effects associated with mammary involution on transfer of immunoglobulin and especially on the selective transfer of IgG1 into mammary secretion of cows approaching parturition has been determined. This was carried out by measuring the changes in the concentration of IgG1, IgG2, IgM and IgA in serum and mammary secretion of 5 cows in which two mammary glands were milked continuously (twice daily) during the period preceding parturition, while the other two glands were allowed to undergo normal involution. In the secretion of unmilked glands of all cows there was a substantial increase in the concentration of IgG1 as cows approached parturition. In contrast, the increases in the concentration of IgG1 and in the selective index for IgG1 of milked glands were either virtually non-existent (1 cow) or generally reduced in magnitude and delayed in time of onset (4 cows). It is clear from the results that continued milking of a mammary gland throughout pregnancy tends to maintain milk production in the milked gland and at the same time reduces the massive selective transfer of IgG1 into secretion of that gland.

Animals↗

PubMed1975

The origin of the immunoglobulins in intestinal lymph of sheep.

Various immunoglobulins were labelled with radioactive iodine and their distribution between intestinal lymph and plasma followed in order to determine the origin of the immunoglobulins found in intestinal lymph. By comparing specific activities in plasma and lymph, it was computed that 25 percent of the IgG1 and IgG2 and 90 percent of the IgA in intestinal lymph were locally synthesised. The results suggest that virtually all of the IgA and a proportion of the IgG1 computed to be synthesised locally were derived from plasma cells of corresponding specificity in the lamina propria of the intestine.

Animals↗

PubMed1975

The effect of glucocorticoid on immunoglobulin secretion into colostrum in cows.

The effect of corticosteroid-induced parturition on transfer of immunoglobulin into mammary secretion of cows has been studied. Seven non-lactating cows in late gestation were injected intramuscularly with a long-acting synthetic glucocorticoid and the concentrations of IgG-1 and IgG-2 were followed in blood serum and mammary secretion which were collected before and after parturition. Within 1 week of injection the udder became distended with secretion identical in appearance to mature milk. In contrast to the situation in normal cows approaching parturition, both the concentration of IgG-1 in secretion and the selective index of IgG-1 decreased after the glucocorticoid injection. A feature of the results were absence in treated cows of the characteristic decrease in serum concentration of IgG-1 just before parturition. It is concluded that glucocorticoid treatment of cows in late pregnancy results in a decreased availability of colostral immunoglobulin to the newborn calf.

Analysis of Variance↗

PubMed1975

The influence of systemic immunisation during mammary involution on subsequent antibody production in the mammary gland.

The primary purpose of the experiments reported in this paper was to determine whether a powerful systemic antigenic stimulus, given at the time of mammary involution, would affect the level of specific antibody in milk secreted during the ensuing lactation. The results showed that a single systemic administration of antigen with adjuvant, during mammary involution, is an efficient means of inducing high titres of specific antibody in milk in the subsequent lactation. Furthermore, such antibody belongs mainly to the IgA and IgM classes of immunoglobulin. These results suggest that the antibody is produced locally in the mammary gland by sensitised cells of the lymphocyte-plasma cell series, which infiltrate the tissue during the early stages of mammary involution and then become sessile.

Animals↗

PubMed1975

Antibody responses to neonatal immunisation in calves.

Antibody responses were measured in colostrum-fed (CF) and colostrum-deprived (CD) calves immunised at ages varying from birth to four months using a variety of antigens with and without adjuvant. In addition immunoglobulin production in CD calves over the same period was compared with that of CF calves. A marked unresponsiveness to antigens injected at birth was observed if maternal antibody specific for the antigen used was present in the circulation. However, significant responses to all antigens tested occurred in CD calves and also in CF calves immunised with an antigen (egg albumin) to which there was no maternal antibody. Since these responses were not as great as those in older calves immunised similarly it is clear that age was influencing the response. It was also found that subsequent responsiveness was not significantly enhanced or impaired by neonatal exposure to antigen. With respect to immunoglobulin production the results conclusively demonstrated that endogenous production occurred much earlier in CD calves than CF calves and even after 128 days the serum concentrations of IgG1 and IgA in CD calves exceeded those for CF calves. Thus it appears that the most important consideration in immunological responsiveness of neonates is not so much immaturity of the lymphoid system as the effects of maternal antibody on the cells in that system.

Agglutination Tests↗

PubMed1974