Colostral antibody-mediated and cell-mediated immunity contributes to innate and antigen-specific immunity in piglets

Abstract

Immunoglobulins and immune cells are critical components of colostral immunity; however, their transfer to and function in the neonate, especially maternal lymphocytes, is unclear. Cell-mediated and antibody-mediated immunity in sow blood and colostrum and piglet blood before (PS) and after (AS) suckling were assessed to investigate transfer and function of maternal immunity in the piglet. CD4, CD8, and γδ lymphocytes were found in sow blood and colostrum and piglet blood PS and AS; each had a unique T lymphocyte profile. Immunoglobulins were detected in sow blood, colostrum, and in piglet blood AS; the immunoglobulin profile of piglet serum AS mimicked that of sow serum. These results suggest selectivity in lymphocyte concentration into colostrum and subsequent lymphocyte transfer into the neonate, but that immunoglobulin transfer is unimpeded. Assessment of colostral natural killer activity and antigen-specific proliferation revealed that colostral cells are capable of influencing the innate and specific immune response of neonatal pigs.

Keywords: 7-aminoactinomycin D; 7AAD; AMI; APC; AS; CFSE; CMC; CMI; Colostrum; ELISA; IgA; IgG; M. hyopneumoniae; Maternally derived immunity; Mycoplasma hyopneumoniae; NK; Neonate; PBMC; PS; Passive transfer; S:P ratio; Swine; T lymphocyte; after-suckling; antibody-mediated immunity; antigen presenting cell; carboxyfluorescein diacetate succinimidyl ester; cell-mediated immunity; colostral mononuclear cells; conA; concanavalin A; enzyme linked immunosorbant assay; immunoglobulin A; immunoglobulin G; natural killer; peripheral blood mononuclear cell; pre-suckling; sample to positive ratio.

Figure 1. T lymphocyte distribution in sow blood and colostrum and in piglet blood before and after colostrum ingestion

Mononuclear cells were isolated from sow blood or colostrum, phenotyped with swine specific γδ, CD8, or CD4 monoclonal antibodies (n=16), and analyzed via flow cytometry. (A) Representative flow cytometric analysis of T lymphocyte subpopulations in sow blood (dark gray) and colostrum (black); light gray represents unstained control. (B) Percentages of T lymphocyte subsets in sow blood and colostrum, n=16. (C) Percentages of T lymphocyte subsets in blood from piglets prior to colostrum ingestion (pre-suckling) and again at 24 h (after-suckling), n=34.Variance is given by standard error. Samples with same letters are significantly different; for samples marked “a,” p=0.001, for samples marked “b” p=0.0001.

Figure 1. T lymphocyte distribution in sow blood and colostrum and in piglet blood before and after colostrum ingestion

Mononuclear cells were isolated from sow blood or colostrum, phenotyped with swine specific γδ, CD8, or CD4 monoclonal antibodies (n=16), and analyzed via flow cytometry. (A) Representative flow cytometric analysis of T lymphocyte subpopulations in sow blood (dark gray) and colostrum (black); light gray represents unstained control. (B) Percentages of T lymphocyte subsets in sow blood and colostrum, n=16. (C) Percentages of T lymphocyte subsets in blood from piglets prior to colostrum ingestion (pre-suckling) and again at 24 h (after-suckling), n=34.Variance is given by standard error. Samples with same letters are significantly different; for samples marked “a,” p=0.001, for samples marked “b” p=0.0001.

Figure 1. T lymphocyte distribution in sow blood and colostrum and in piglet blood before and after colostrum ingestion

Mononuclear cells were isolated from sow blood or colostrum, phenotyped with swine specific γδ, CD8, or CD4 monoclonal antibodies (n=16), and analyzed via flow cytometry. (A) Representative flow cytometric analysis of T lymphocyte subpopulations in sow blood (dark gray) and colostrum (black); light gray represents unstained control. (B) Percentages of T lymphocyte subsets in sow blood and colostrum, n=16. (C) Percentages of T lymphocyte subsets in blood from piglets prior to colostrum ingestion (pre-suckling) and again at 24 h (after-suckling), n=34.Variance is given by standard error. Samples with same letters are significantly different; for samples marked “a,” p=0.001, for samples marked “b” p=0.0001.

Figure 2. Immunoglobulin G and A concentrations in sow serum and colostrum and in piglet serum before and after colostrum ingestion

IgG and IgA concentrations from (A) sow serum and colostral whey (n=16) and (B) in piglet serum before colostrum ingestion (pre-suckling) and 24 h later (after-suckling) (n=34) were determined by ELISA. Variance is given by standard error. Samples with same letters are significantly different, p<0.001

Figure 2. Immunoglobulin G and A concentrations in sow serum and colostrum and in piglet serum before and after colostrum ingestion

IgG and IgA concentrations from (A) sow serum and colostral whey (n=16) and (B) in piglet serum before colostrum ingestion (pre-suckling) and 24 h later (after-suckling) (n=34) were determined by ELISA. Variance is given by standard error. Samples with same letters are significantly different, p<0.001

Figure 3. Natural killer activity of colostral and peripheral mononuclear cells

Innate natural killer activity was used to assess the functional ability of mononuclear cells from sow colostrum (CMC) and blood (PBMC) of sows and piglets, before (PS) and after (AS) colostrum ingestion. Variance is given by standard error. Samples with same letters are significantly different, p<0.05.

Figure 4. Mycoplasma hyopneumoniae specific antibodies in serum and colostrum of unvaccinated and vaccinated sows

Mycoplasma hyopneumoniae specific antibodies were measured in serum and colostrum of unvaccinated (n=10) and vaccinated (n=10) sows using the Idexx HerdCheck ELISA. Positive and negative antibody status was based on sample to positive (S:P) ratio. Samples with the same letters are significantly different, p<0.05

Figure 5. Antigen specific proliferation by mononuclear cells isolated from piglets before and after colostrum ingestion and from sow colostrum

Mononucelar cells from sow colostrum (CMC; n=10) and from piglet blood (PBMC; n=20) before (PS) and after (AS) colostrum ingestion were stimulated with Mycoplasma hyopneumoniae antigen. Proliferation was assessed by flow cytometry. Antigen specific proliferation was compared between colostrum of vaccinated and unvaccinated sows and piglets receiving colostrum from vaccinated and unvaccinated sows. Variation is expressed as standard error; samples with different letters indicate significance at p<0.05.