Inadequate consumption of colostrum can negatively affect calf health and survival. The serum immunoglobulin G (IgG) concentrations of 935 beef calves from 152 herds in Alberta and Saskatchewan have been described, using radial immunodiffusion. The determinants and health effects of serum IgG concentrations were studied in 601 calves sampled between 2 and 8 days of age. Of these calves, 6% had failure of passive transfer and an additional 10% had marginal passive transfer. Serum IgG concentrations were lower in calves born to a heifer, as a twin, or experiencing dystocia. The odds of both calf death and treatment were increased in calves with serum IgG concentrations below 24 g/L; a threshold notably higher than the 16 g/L usually considered as providing adequate passive transfer. The finding of 1/3 of calves with serum IgG concentrations less than 24 g/L suggests that calfhood treatments and mortality could be decreased by ensuring that high risk calves consume colostrum.

Enterocin C (EntC), a class IIb bacteriocin was purified from culture supernatants of Enterococcus faecalis C901, a strain isolated from human colostrum. Enterocin C consists of two distinct peptides, named EntC1 and EntC2, whose complementary action is required for full antimicrobial activity. The structural genes entC1 and entC2 encoding enterocins EntC1 and EntC2, respectively, and that encoding the putative immunity protein (EntCI) are located in the 9-kb plasmid pEntC, harboured by E. faecalis C901. The N-terminal sequence of both antimicrobial peptides revealed that EntC1 (4284 Da) is identical to Ent1071A, one of the two peptides that form enterocin 1071 (Ent1071), a bacteriocin produced by E. faecalis BFE 1071. In contrast, EntC2 (3867 Da) presents the non-polar alanine residue at position 17 (Ala(17)) instead of the polar threonine residue (Thr(17)) in Ent1071B, the second peptide constituting Ent1071. In spite of peptide similarities, EntC differs from Ent1071 in major aspects, including the complementary activity among its constitutive peptides and its wider inhibitory spectrum of activity. Different amphiphilic alpha-helical conformations between EntC2 and Ent1071B could explain both, acquired complementary activity and increased antimicrobial spectrum.

Intimin is essential for attaching and effacing lesions by pathogens such as enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC), and the antigenic polymorphism of intimin determines distinct subtypes. Our aim was to investigate the presence of immunoglobulin G (IgG) and IgA antibodies reactive to alpha, beta and gamma intimins in serum and colostrum from healthy Brazilian adults. We found seric IgG and secretory IgA antibodies reactive to conserved and variable regions of alpha, beta and gamma intimins and a positive correlation between the concentrations of these antibodies in both serum and colostrum that suggested cross reactivity among anti-intimin antibodies, as was confirmed by immunoblotting and absorption. The concentrations of anti-conserved region antibodies were higher than those of variable region antibodies. The presence of antibodies reactive to EHEC antigens could result from contact with EPEC or with other bacteria of the environment even though this bacterium is not frequent in Brazil, and suggests possible protection against EHEC.

Human colostrum contains many bioactive factors that must promote the development of intestinal mucosal immunity in infants. Especially, the presence of certain cytokines such as transforming growth factor (TGF)-beta or IL-10 has been of great interest for IgA production as a function of mucosal immune response. In the present study, we attempted to investigate whether unidentified factors inducing generation of IgA-producing cells from naive B cells might exist in colostrum. For this purpose, colostrum samples were directly added to a culture consisting of naive B cells and dendritic cells from cord blood and CD40 ligand-transfected L cells, comparing with recombinant IL-10 (rIL-10) and/or rTGF-beta. It was noted that most colostrum samples alone were able to induce IgA-secreting cells at higher levels than rIL-10 and/or rTGF-beta. IgA-inducing activity of colostrum was abolished by neither anti-neutralizing mAbs against IL-10 nor TGF-beta, though partially by anti-IL-6 mAb. We prepared partially purified fractions from both pooled colostrums with and without IgA-inducing activity and comparatively performed quantitative proteomic analysis by two-dimensional difference gel electrophoresis followed by liquid chromatography-mass spectrometry. As a result, syntenin-1 was identified as a candidate for IgA-inducing protein in colostrum. Western blot analysis indicated that levels of syntenin-1 in colostrum samples were correlated with their IgA-inducing activities. Moreover, we demonstrated that recombinant syntenin-1 could induce preferentially IgA production from naive B cells. These results suggest that syntenin-1 serves as one of IgA-inducing factors for B cells.

The objective of this study was to determine the effects of feeding heat-treated colostrum or unheated colostrum of different bacterial counts on passive transfer of immunity in neonatal dairy calves. First milking colostrum was collected from Holstein cows, frozen at -20 degrees C, and then thawed and pooled into a single batch. One-third of the pooled colostrum was transferred into plastic containers and frozen at -20 degrees C until needed for feeding (unheated-low bacteria). Another third was heat-treated at 60 degrees C for 30 min and then frozen at -20 degrees C until needed for feeding (heat-treated). The final third of colostrum was transferred into plastic containers, stored at 20 degrees C for bacteria to grow for 24 h (unheated-high bacteria), and then frozen at -20 degrees C until needed for feeding. A total of 30 Holstein bull calves weighing >or=30 kg at birth were systematically enrolled into 1 of the 3 treatment groups. Calves were separated from their dams at birth before suckling occurred. Before colostrum was fed, a jugular blood sample was collected from each calf. The first feeding consisted of 3.8 L of colostrum containing, on average, 68 g of IgG/L using an esophageal feeder between 1.5 and 2 h after birth. For the second and third feeding pasteurized whole milk at 5% of birth weight was fed. Blood samples were collected before colostrum feeding and at 24 and 48 h of age to determine serum total protein (STP) and IgG concentrations. Heat treatment of colostrum at 60 degrees C for 30 min reduced colostrum bacteria concentration yet maintained colostral IgG concentration and viscosity at similar levels to the control treatment. Calves fed heat-treated colostrum had significantly greater STP and IgG concentrations at 24 h and greater apparent efficiency of absorption (AEA) of IgG (STP = 62.5 g/L; IgG = 26.7 g/L; AEA = 43.9%) compared with calves fed unheated-low bacteria colostrum (STP = 57.0 g/L; IgG = 20.2 g/L; AEA = 35.4%) or unheated-high bacteria colostrum (STP = 56.2 g/L; IgG = 20.1 g/L; AEA = 32.4%). High bacteria load in colostrum did not interfere with total protein or IgG absorption or AEA.