Passive immune transfer in puppies

Abstract

The puppy, born without immunoglobulins G (IgG), acquires a passive systemic immunity thanks to colostrum intake during the two first days of life. The quality of passive immune transfer (i.e. blood IgG concentration at two days of age), highly variable between litters and between puppies within litters, depends mainly on the time elapsed between birth and ingestion of colostrum, with limited influence of colostrum IgG concentration. Deficit in passive immune transfer, impacting puppy's health and neonatal mortality rate, can be indirectly diagnosed through blood gammaglutamyltransferases assay and evaluation of growth rate over the two first days of life. In the absence of maternal colostrum, few homo- and heterospecific immune sources are available and canine colostrum banking remains the optimal solution. Whereas passive immune transfer is crucial for survival during the neonatal period, it later interferes with response to vaccination. In addition to systemic passive immune transfer, maternal antibodies (mainly IgA) would provide local (digestive) immunity, ensuring mid-term protection of the puppies' gut together with probably long term training of the digestive immune system.

Keywords: Colostrum; Digestive tract; Dog; Growth; Immunoglobulins G; Neonatology.

Fig. 1

Pattern of immunoglobulins G, M and A concentrations in puppies’ blood. n=57 Beagle puppies from one kennel, with free suckling. Mean ± standard deviation. ELISA assay (method described in Chastant-Maillard et al., 2012).

Fig. 2

Heterogeneity of passive immune transfer (evaluated through blood IgG concentration at Day 2 of age) inter and intra litter. n = 54 Beagle puppies from 9 litters from one kennel, with free suckling. The horizontal line indicates the threshold defining failure of passive immune transfer (2.3 g/L). In Litters 5, 6 and 9, all puppies reached a sufficient passive immune transfer; in Litter 4, all were in failure of passive immune transfer; within Litter 1 and 7, passive immune transfer was heterogeneous, some above, others below the threshold.

Fig. 3

Frequency of suckling (in % of suckling time) of each mammary gland during the first 24 h of life. Suckling behavior of 35 Labrador puppies followed by visual observation (Viaud, 2018).

Fig. 4

Theoretical estimation of the minimal IgG concentration in colostrum for appropriate passive immune transfer. [1] With a blood volume equivalent to 7% body weight and a hematocrit of the newborn puppy at 50%, the total volume of serum within a puppy is 3.5 milliliters for 100 g body weight (100 g x 7% x (1–hematocrit)). [2] The minimal serum concentration to be reached by the puppy at two days of age is 2.3 g/l, representing an absorbed IgG amount of 8.05 mg (2.3×serum volume). [3] The IgG absorption rate was 30% in average between birth and 8 h of life (Chastant-Maillard et al., 2012). An 8.05 mg absorbed amount corresponds to 26.8 mg ingested IgG. [4] A puppy ingests 4 ml/100 g body weight and performs 2 meals over the period of intestinal permeabilty: circulating IgG are thus absorbed from 8 ml colostrum per 100 g body weight. [5] The minimal colostrum concentration is 3.4 g/l (ingested IgG×1000/8).

Fig. 5

CPV2-specific antibody titers (histogram) and fecal viral loads (squares at Day39, 45, 53 of age). Puppies (n=79 from various breeds within one kennel) were classified in two groups depending on their titer at Day2 (hemagglutination inhibition): 45 puppies with HI titer > 1:160 (black), 34 puppies with HI ≤1:160 (grey). The protective titer is 1:80. Viral load was evaluated by RT PCR (significant above 10² copies/ml). NeoCare unpublished data. Methods are described by Mila et al. (2014b).