Chicken Immunoglobulin G [Rhodamine]

The objective of this study was to evaluate the passive transfer (PT), health and performance of calves fed differing volumes of a colostrum replacer and/or maternal colostrum. Newborn calves were colostrum fed within 2 h of birth as follows:1) 2 L (192.78 +/- 11.55 g of IgG) of maternal colostrum (2MC); 2) 4 L of maternal (387.69 +/- 12.10 g of IgG ) colostrum (4MC); 3) 2 L (196.16 +/- 11.48 g of IgG) of maternal colostrum + one package (100 g IgG in 1.4 L) of colostrum replacer (2MC1CR); 4) 2 packages of colostrum replacer (2CR) and 5) 2 packages of colostrum replacer given within 2 h following birth + one package of colostrum replacer given between 6 and 8 h after birth (3CR). Calves were individually housed and following colostrum feeding(s), were fed 6 L/d of milk replacer with ad libitum access to water and calf starter. Passive transfer as assessed by serum immunoglobulin (Ig) levels were high (mean values of 21.8-25.9 g IgG/L) and did not differ signficantly among groups (P > 0.05). Calves fed larger volumes of colostrum and thus greater Ig mass had lower apparent efficiency absorption (P < 0.0001). There was no difference among colostrum feeding protocols in health parameter outcomes, including fecal score, days with diarrhea, days with fever, number of treatments for diarrhea and number of treatments for pneumonia (P > 0.05). However, the number of treatments for cattle tick fever differed among groups (P = 0.0042). The mean weight and ADG, as well as the blood parameters including total protein, albumin, glucose, BHBA, NEFA and insulin levels, evaluated during the pre-weaning period, did not differ among the groups (P > 0.05). While group numbers were modest (10 calves/treatment), this study shows that all protocols used can deliver high levels of passive transfer suggesting that either good quality maternal colostrum and/or the colostrum replacer evaluated may be recommended for newborn calf colostrum management.

The success of antibody therapeutics is strongly influenced by their multifunctional nature that couples antigen recognition mediated by their variable regions with effector functions and half-life extension mediated by a subset of their constant regions. Nevertheless, the monospecific IgG format is not optimal for many therapeutic applications, and this has led to the design of a vast number of unique multispecific antibody formats that enable targeting of multiple antigens or multiple epitopes on the same antigen. Despite the diversity of these formats, a common challenge in generating multispecific antibodies is that they display suboptimal physical and chemical properties relative to conventional IgGs and are more difficult to develop into therapeutics. Here we review advances in the design and engineering of multispecific antibodies with drug-like properties, including favorable stability, solubility, viscosity, specificity and pharmacokinetic properties. We also highlight emerging experimental and computational methods for improving the next generation of multispecific antibodies, as well as their constituent antibody fragments, with natural IgG-like properties. Finally, we identify several outstanding challenges that need to be addressed to increase the success of multispecific antibodies in the clinic.