Accumulation of CD25+ CD4+ T-cells in the draining lymph node during the elicitation phase of DNCB-induced contact hypersensitivity in lambs

Effects of feed-borne Fusarium mycotoxins on hematology and immunology of turkeys

Feeding grains naturally-contaminated with Fusarium mycotoxins has been shown to alter the metabolism and performance of turkeys. The objectives of the current experiment were to examine the effects of feeding turkeys with grains naturally contaminated with Fusarium mycotoxins on their hematology and immunological indices (including functions), and the possible protective effect of feeding a polymeric glucomannan mycotoxin adsorbent (GMA). Two hundred twenty-five 1-d-old male turkey poults were fed corn, wheat, and soybean meal-based starter (0 to 3 wk), grower (4 to 6 wk), developer (7 to 9 wk), and finisher (10 to 12 wk) diets formulated with uncontaminated grains, contaminated grains, or contaminated grains with 0.2% GMA. The chronic consumption of Fusarium mycotoxins caused minor and transient changes in hematocrit (0.33 L/L) and hemoglobin (10(6) g/L) concentrations as well as in blood basophil (0.13 x 10(9)/L) and monocyte counts (3.42 x 10(9)/L) compared with controls. Supplementation of the contaminated diet with GMA prevented these effects on blood cell counts. Biliary IgA concentrations were significantly increased (4.45-fold) when birds were fed contaminated grains compared with controls, but serum IgA concentrations were not affected. Contact hypersensitivity to dinitrochlorobenzene, which is a CD8+ T-cell-mediated delayed-type hypersensitivity response, was decreased (48%) by feed-borne mycotoxins compared with the control. By contrast, the primary and secondary antibody response to sheep red blood cells, a CD4+ T-cell-mediated response, was not affected. It was concluded that chronic consumption of grains naturally contaminated with Fusarium mycotoxins exerts only minor adverse effects on the hematology and some immunological indices of turkeys. Consumption of grains naturally contaminated with Fusarium mycotoxins may, however, increase the susceptibility of turkeys to infectious agents against which CD8+ T cells play a major role in defense.

Accuracy of adults' recall of childhood social class: findings from the Aberdeen children of the 1950s study

BACKGROUND

Although adult reported childhood socioeconomic position has been related to health outcomes in many studies, little is known about the validity of such distantly recalled information. This study evaluated the validity of adults' reports of childhood paternal social class.

METHODS

Data are drawn from the Aberdeen children of the 1950s study, a cohort of 12 150 people born in Aberdeen (Scotland) who took part in a school based survey in 1962. In this survey, two indices of early life socioeconomic position were collected: occupational social class at birth (abstracted from maternity records) and occupational social class in childhood (reported during the 1962 survey by the study participants). Between 2000 and 2003, a questionnaire was mailed to traced middle aged cohort members in which inquiries were made about their fathers' occupation when they were aged 12 years. The level of agreement between these reports and prospectively collected data on occupational social class was assessed.

RESULTS

In total, 7183 (63.7%) persons responded to the mid-life questionnaire. Agreement was moderate between social class of father recalled in adulthood and that measured in early life (kappa statistics were 0.47 for social class measured at birth, and 0.56 for social class reported by the child). The relation of occupational social class to birth weight and childhood intelligence was in the expected directions, although weaker for adults' reports in comparison with prospectively gathered data.

CONCLUSIONS

In studies of adult disease aetiology, associations between childhood social class based on adult recall of parental occupation and health outcomes are likely to underestimate real effects.

Migratory monocytes and granulocytes are major lymphatic carriers ofSalmonellafrom tissue to draining lymph node

Dendritic cells (DC) are recognized as sentinels, which capture antigens in tissue and migrate to the lymph node, where they initiate immune responses. However, when a vaccine strain of green fluorescent protein-expressing Salmonella abortusovis (SAO) was inoculated into sheep oral mucosa, it induced accumulation of myeloid non-DC in the subcapsular sinus and paracortex of the draining lymph node, and SAO was mainly found associated with these cells (granulocytes and macrophages) but rarely with DC. To analyze how bacteria reached lymph nodes, we used cervical pseudo-afferent lymph duct catheterization. We showed that Salmonella administered in the oral mucosa were traveling free in lymph or associated with cells, largely with lymph monocytes and granulocytes but less with DC. SAO also induced a strong influx of these phagocytic cells in afferent lymph. Migrating DC presented a semi-mature phenotype, and SAO administration did not alter their expression of major histocompatibility complex type 2 and coactivation molecules. Compared with blood counterparts, lymph monocytes expressed lower levels of CD40, and granulocytes expressed higher levels of CD80. The data suggest that immunity to bacteria may result from the complex interplay between a mixture of phagocytic cell types, which transport antigens and are massively recruited via lymph to decisional lymph nodes.

Probing leukocyte traffic in lymph from oro-nasal mucosae by cervical catheterization in a sheep model

Lymph nodes are instructed via the lymph about ongoing events in tissues both during the steady state and under provoked inflammation. In order to probe for tissue-to-node transduction mechanisms, we have developed a novel in vivo technique of pseudo-afferent lymph collection from the oro-nasal mucosae which represent the main portals of entry of micro-organisms and efficient routes for vaccination. After lateral lymph node resection of the head, a network of lymph ducts was reconstructed as checked by lymphography. Subsequent catheterization of the cervical lymph duct allowed the collection of cells that were shown to originate from the oro-nasal mucosae. These cells included dendritic cells, monocytes, granulocytes, memory CD45RAneg CD2pos integrin beta7lo CD4 T cells, CD25pos CD4, CD8, gamma/delta T cells, and B lymphocytes. This approach, which permits lymph collection over several weeks, opens a valuable and unique way to study leukocyte and particulate (micro-organisms, vaccines) trafficking from head tissue to nodes under homeostastic and immuno-stimulatory conditions in a highly physiological setting.

Effects of feeding blends of grains naturally contaminated with Fusarium mycotoxins on performance, metabolism, hematology, and immunocompetence of ducklings

Experiments were conducted to determine the effects of feeding grains naturally contaminated with Fusarium mycotoxins on performance, metabolism, hematology, and immune competence of ducklings. Four hundred sixty-four 1-d-old White Pekin male ducklings were fed starter (0 to 2 wk), grower (3 to 4 wk), and finisher (5 to 6 wk) diets formulated with uncontaminated grains, a low level of contaminated grains, a high level of contaminated grains, or the higher level of contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent. Body weight gains, feed consumption, and feed efficiency were not affected by diet. However, consumption of contaminated grains decreased plasma calcium concentrations after 2 wk and plasma uric acid concentrations at the 4-wk assessment point. Mean corpuscular hemoglobin concentrations and hematocrit decreased when ducks were fed contaminated grains for 4 or 6 wk, respectively. In contrast, total numbers of white blood cells and lymphocytes increased transiently in birds fed contaminated grains for 4 wk. The antibody response to sheep red blood cells (CD4+ T cell dependent) and the cell-mediated response to phytohemagglutinin-P (also CD4+ T cell dependent) were not affected by diet, but consumption of contaminated grains for 6 wk decreased the duration of peak cell-mediated response to dinitrochlorobenzene (CD8+ T cell dependent) assessed in a skin test. Feeding grains naturally contaminated with Fusarium mycotoxins, even at levels widely regarded as high, exerted only minor adverse effects on plasma chemistry and hematology of ducklings, and production parameters were unaffected in this avian species. Mycotoxin-contaminated feeds may, however, render these animals susceptible to infectious agents such as viruses against which the CD8+ T cell provides necessary defence. Glucomannan mycotoxin adsorbent was not effective in preventing alterations caused by Fusarium mycotoxins.