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The interleukin-2 (IL-2) assay has become a useful tool for examining the cellular immune response. Because of a lack of avian IL-2-dependent cell lines, the avian IL-2 assay in its present state, however, is not currently as powerful as its mammalian counterpart in effectively evaluating levels of IL-2 activity. The use of an avian IL-2 reference standard, Percoll-enriched populations of lymphoblasts, and sample collection times were examined to optimize the assay for comparing levels of IL-2 activity in a large number of birds. The reference standard was effective in accounting for assay-to-assay variance. Percoll-enriched populations of responding lymphoblasts were more sensitive to IL-2 than nonseparated populations of cultured peripheral blood lymphocytes. Levels of IL-2 activity of cells isolated from the same bird did not change within a 1-week period, although differences did approach significance. In addition, levels of IL-2 activity differed between genetically distinct populations.

The effects of adrenaline on kinetically-distinct compartments of exchangeable calcium in the spontaneously-beating perfused rat heart were investigated under steady-state conditions using a 45Ca2+ outflow technique together with a nonlinear least-squares curve fitting procedure and 51Cr-EDTA to monitor the loss of freely-diffusible Ca2+ from the extracellular space. In addition to Ca2+ distributed in the vascular (compartment 1) and interstitial (compartment 2) spaces, the minimum number of kinetically-distinct compartments of cellular exchangeable Ca2+ (which include Ca2+ bound to extracellular sites on the sarcolemma) required to fit the data (compartments 3, 4 and 5) was three. A system in which cellular compartment 3 is linked to the vascular space and compartments 4 and 5 are linked to the interstitial space was consistent with the data. For hearts perfused under control conditions, the fractional transfer rates for Ca2+ outflow from cellular compartments 3, 4 and 5 were 0.70, 0.11 and 0.017 min-1, respectively. Adrenaline increased the quantity of exchangeable Ca2+ in compartment 5 and decreased that present in the compartment 4. Evidence that compartment 5 includes mitochondrial exchangeable Ca2+ is discussed. It is concluded that one of the actions of adrenaline on the heart is to increase the quantity of exchangeable Ca2+ in the mitochondria.

Chickens from the Iowa State S1 White Leghorn line, selected for characteristics of Ea-B serotype, humoral immune response to glutamic acid-alanine-tyrosine (Ir-GAT), and response to Rous sarcoma virus (RSV)-induced tumors, were evaluated for genetic resistance to Marek's disease (MD). In the first two trials, sublines that were triple homozygous for the three traits were challenged with MD virus. Birds of the B1B1 blood type were significantly (P less than .001) more resistant to MD than chickens of the B19B19 blood type. High responders to GAT were significantly (P less than .001) more resistant to MD virus than low responders. The RSV classification had no detectable association with MD resistance. Chickens challenged with MD virus in the third trial were an F2 population produced from inter se matings of S1 chickens heterozygous for the three traits under selection. Data from this trial confirmed increased MD resistance of chickens possessing the B1B1 blood type when associated with genes encoding high immune response to GAT.

Plasma samples from more than 300 inbred chickens were screened by using an immunofixation technique with antibody against the fourth component of complement (C4) from humans. Precipitation patterns of plasma from adult male and sexually immature birds, either male or female, were identical. Plasma from egg-laying hens demonstrated a distinctly different precipitation pattern compared with plasma of other birds, with one additional band appearing 14 to 9 days before production of the first egg. The banding pattern could not be induced in males by progesterone injection and remained unchanged in molted female birds.

Immunocompetence of the Iowa State University S1 White Leghorn chicken line was studied. This line was divided into eight sublines based upon erythrocyte antigen B (Ea-B) allele (B1B1 or B19B19), antibody response to glutamic acid60-alanine30-tyrosine10 (GAT) (high or low), and response to Rous sarcoma virus-induced tumors (progression or regression). Antibody responses to Pasteurella multocida (PM), Mycoplasma gallisepticum (MG), and infectious bursal disease virus vaccines were evaluated by enzyme-linked immunosorbent assay. Phagocytic activity and T cell-mediated response were measured by carbon clearance and phytohemagglutinin (PHA) injection assays, respectively. Significant haplotype (subline) differences and sire family differences were observed in all three measurements. Significant sex differences were observed in phagocytic activity and T cell-mediated responses. Haplotypes with high antibody responses to GAT had significantly higher antibody titers to PM and MG vaccines than haplotypes with low antibody responses. Significant positive correlations were observed between antibody levels to the two vaccines. A significant negative correlation was seen between phagocytic activity and T cell-mediated response of females. The data suggest that the total immunocompetence profile of an individual must be considered to select for optimum immune responsiveness.

Studies were conducted to compare the cell-mediated immune response of the Delayed Amelanotic (DAM) line of chickens with that of the line from which it originated, the Brown (BR) line, and a distantly related environmental control, the Light Brown Leghorn (LBL) line. Assays used to evaluate cell-mediated immunity were graft versus host (GvH) splenomegaly and the phytohemagglutinin (PHA) skin response. The three genetic stocks showed different responses to both tests with a variation in ranking between the tests. The GvH response of BR birds was significantly greater (P less than .01) than that of DAM birds, which was in turn significantly greater (P less than .001) than that of LBL birds. In the PHA skin test, the responses of BR and LBL birds did not differ but were significantly greater (P less than .001) than those of DAM line birds.

The role of turkey complement in a serum bactericidal reaction was determined using serum-sensitive and serum-resistant Escherichia coli isolated from turkeys. Inactivation of complement by heating serum (56 C for 40 minutes) or by treating serum with 10 mM EDTA eliminated bactericidal activity. Serum-sensitive E coli organisms were killed by turkey serum treated with 10 mM ethylene glycol-bis-beta-(aminoethyl ether)-N,N,N',N'-tetraacetic acid and 5 mM MgCl2. Exposure of normal turkey serum to serum-sensitive or serum-resistant E coli resulted in equivalent reductions in hemolytic activity of serum. Treatment of serum-resistant E coli with antibody rendered the bacteria sensitive to bactericidal effects of normal turkey serum. Serum-sensitive E coli organisms were readily killed by an alternative complement pathway, serum-sensitive and serum-resistant E coli activated the complement system equally well, and antibody was required for complement-mediated killing of certain serum-resistant E coli organisms from turkeys.

The kinetic properties of exchangeable Ca2+ in isolated guinea-pig heart mitochondria were studied at 25 degrees C in the presence of 0.9 mM free Mg2+, ATP, phosphate ions and 0.4 - 0.5 microM free Ca2+ using a 45Ca2+ exchange technique. The simplest system which was found to be consistent with the data was one in which two kinetically-distinct compartments of exchangeable Ca2+ are present in the mitochondria. In the presence of 6 mM Na and at 0.4 microM free Ca2+, the fractional transfer rates for the transport of Ca2+ from these compartments were found to be 0.6 and 0.05 min-1 and the quantities of exchangeable Ca2+ 0.04 and 0.2 mumol/g wet wt heart, respectively. The amount of 45Ca2+ exchanged increased when the concentration of inorganic phosphate was increased, and decreased slightly when the concentration of free Mg2+ was increased from 1 mM to 3 mM. The flux of Ca2+ across the boundaries of both compartments was inhibited by an increase in the concentration of extramitochondrial Na+. The contribution of mitochondrial Ca2+ to compartments of kinetically-distinct exchangeable Ca2+ observed in intact cardiac muscle is briefly discussed.

Body weights at 8, 20, and 32 wk, total egg production, average egg weight, egg production during a 4-wk period, and age at first egg laid were measured in 652 female progeny of heterozygous x heterozygous (F1) or heterozygous x homozygous (backcross) matings of the Iowa State University S1 White Leghorn chicken line. Hens were classified by B-haplotypes (B1 or B19) and haplotype-associated immune responses (high or low) to the amino acid polymer glutamic acid-alanine-tyrosine (Ir-GAT). Body weights were affected by parental mating group, sire, and dam, but they were not affected by haplotype (B/Ir-GAT). Sexual maturity and egg production were not affected by any factors except hatch. Average egg weight was affected by parental mating group, sire, dam, and genotype, with homozygous B19B19 birds having a heavier mean egg weight (41.71 g +/- .20) than homozygous B1B1 Ir-GAT-high and - low birds (40.8 g +/- .38 and 39.2 g +/- .54, respectively); mean egg weights of heterozygous birds were approximately intermediate to the others.