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Changes in leukocyte subsets of pregnant gilts experimentally infected with porcine reproductive and respiratory syndrome virus and relationships with viral load and fetal outcome.

Ladinig A, Gerner W, Saalmüller A, Lunney JK, Ashley C, Harding JC - Vet. Res. (2014)

Bottom Line: Our data also show a greater decrease of naïve B cells, T-helper cells and cytolytic T cells than their respective effector or memory counterparts.Absolute numbers of T cells and γδ T cells were negatively associated with PRRSv RNA concentration in gilt serum over time.Although many questions regarding the immune responses remain unanswered, these findings provide insight and clues that may help reduce the impact of PRRSv in pregnant gilts.

View Article: PubMed Central - PubMed

Affiliation: Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada. andrea.ladinig@vetmeduni.ac.at.

ABSTRACT
In spite of more than two decades of extensive research, the understanding of porcine reproductive and respiratory syndrome virus (PRRSv) immunity is still incomplete. A PRRSv infection of the late term pregnant female can result in abortions, early farrowings, fetal death, and the birth of weak, congenitally infected piglets. The objectives of the present study were to investigate changes in peripheral blood mononuclear cell populations in third trimester pregnant females infected with type 2 PRRSv (NVSL 97-7895) and to analyze potential relationships with viral load and fetal mortality rate. PRRSv infection caused a massive, acute drop in total leukocyte counts affecting all PBMC populations by two days post infection. Except for B cells, cell counts started to rebound by day six post infection. Our data also show a greater decrease of naïve B cells, T-helper cells and cytolytic T cells than their respective effector or memory counterparts. Absolute numbers of T cells and γδ T cells were negatively associated with PRRSv RNA concentration in gilt serum over time. Additionally, absolute numbers of T helper cells may be predictive of fetal mortality rate. The preceding three leukocyte populations may therefore be predictive of PRRSv-related pathological outcomes in pregnant gilts. Although many questions regarding the immune responses remain unanswered, these findings provide insight and clues that may help reduce the impact of PRRSv in pregnant gilts.

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Related in: MedlinePlus

Changes in T helper cells in response to PRRSv infection in pregnant gilts. A)Dot plots: The gating strategy for T helper cells (CD4+) and CD8α-defined subpopulations is demonstrated using representative data from gilt #53. B-D)Line charts: Changes in absolute numbers (mean ± SD) of total T helper cells (yellow), CD8α− T helper cells (light blue), and CD8α+ T helper cells (brown) are presented from 111 INOC and 19 CTRL gilts over time. P-values indicate significant differences between INOC and CTRL gilts on individual days. E)Bar chart: The mean percentages (+SD) of T helper cells expressing CD8α within total CD4+ T cells from INOC and CTRL gilts are presented for the respective study days. Superscript letters indicate significant differences (P < 0.01) between study days within INOC or CTRL gilts.
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Fig7: Changes in T helper cells in response to PRRSv infection in pregnant gilts. A)Dot plots: The gating strategy for T helper cells (CD4+) and CD8α-defined subpopulations is demonstrated using representative data from gilt #53. B-D)Line charts: Changes in absolute numbers (mean ± SD) of total T helper cells (yellow), CD8α− T helper cells (light blue), and CD8α+ T helper cells (brown) are presented from 111 INOC and 19 CTRL gilts over time. P-values indicate significant differences between INOC and CTRL gilts on individual days. E)Bar chart: The mean percentages (+SD) of T helper cells expressing CD8α within total CD4+ T cells from INOC and CTRL gilts are presented for the respective study days. Superscript letters indicate significant differences (P < 0.01) between study days within INOC or CTRL gilts.

Mentions: Absolute T helper cells, identified by a CD3+CD4+ phenotype (Figure 7A, yellow gate), were significantly decreased in INOC gilts on 2 dpi (P < 0.001) and trended lower on 6 dpi (P = 0.044) compared to CTRL (Figure 7B). To investigate their activation/memory status [11], expression of CD8α was analyzed (Figure 7A, brown and light blue gates). Compared to CRTL, INOC gilts had numerically increased numbers of CD8α− T helper cells on 0 dpi (P = 0.033), but numbers decreased significantly on 2 dpi (P < 0.001) (Figure 7C). The decrease in CD8α− T helper cells in INOC gilts was substantial with counts dropping to 22% (0.22 ± 0.1 × 109/L) of 0 dpi counts. Absolute numbers of CD8α+ T helper cells were significantly lower in INOC gilts on 2 dpi (P < 0.001) and 6 dpi (P = 0.003), and trended lower on 19 dpi (P = 0.021) compared to CTRL gilts (Figure 7D). However, given the percentage of T helper cells expressing CD8α increased significantly on 2 dpi (Figure 7E), the drop in total T helper cells on 2 dpi to 42% of the 0 dpi counts was over represented by the CD8α− phenotype, rather than the CD8α+ phenotype.Figure 7


Changes in leukocyte subsets of pregnant gilts experimentally infected with porcine reproductive and respiratory syndrome virus and relationships with viral load and fetal outcome.

Ladinig A, Gerner W, Saalmüller A, Lunney JK, Ashley C, Harding JC - Vet. Res. (2014)

Changes in T helper cells in response to PRRSv infection in pregnant gilts. A)Dot plots: The gating strategy for T helper cells (CD4+) and CD8α-defined subpopulations is demonstrated using representative data from gilt #53. B-D)Line charts: Changes in absolute numbers (mean ± SD) of total T helper cells (yellow), CD8α− T helper cells (light blue), and CD8α+ T helper cells (brown) are presented from 111 INOC and 19 CTRL gilts over time. P-values indicate significant differences between INOC and CTRL gilts on individual days. E)Bar chart: The mean percentages (+SD) of T helper cells expressing CD8α within total CD4+ T cells from INOC and CTRL gilts are presented for the respective study days. Superscript letters indicate significant differences (P < 0.01) between study days within INOC or CTRL gilts.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4265508&req=5

Fig7: Changes in T helper cells in response to PRRSv infection in pregnant gilts. A)Dot plots: The gating strategy for T helper cells (CD4+) and CD8α-defined subpopulations is demonstrated using representative data from gilt #53. B-D)Line charts: Changes in absolute numbers (mean ± SD) of total T helper cells (yellow), CD8α− T helper cells (light blue), and CD8α+ T helper cells (brown) are presented from 111 INOC and 19 CTRL gilts over time. P-values indicate significant differences between INOC and CTRL gilts on individual days. E)Bar chart: The mean percentages (+SD) of T helper cells expressing CD8α within total CD4+ T cells from INOC and CTRL gilts are presented for the respective study days. Superscript letters indicate significant differences (P < 0.01) between study days within INOC or CTRL gilts.
Mentions: Absolute T helper cells, identified by a CD3+CD4+ phenotype (Figure 7A, yellow gate), were significantly decreased in INOC gilts on 2 dpi (P < 0.001) and trended lower on 6 dpi (P = 0.044) compared to CTRL (Figure 7B). To investigate their activation/memory status [11], expression of CD8α was analyzed (Figure 7A, brown and light blue gates). Compared to CRTL, INOC gilts had numerically increased numbers of CD8α− T helper cells on 0 dpi (P = 0.033), but numbers decreased significantly on 2 dpi (P < 0.001) (Figure 7C). The decrease in CD8α− T helper cells in INOC gilts was substantial with counts dropping to 22% (0.22 ± 0.1 × 109/L) of 0 dpi counts. Absolute numbers of CD8α+ T helper cells were significantly lower in INOC gilts on 2 dpi (P < 0.001) and 6 dpi (P = 0.003), and trended lower on 19 dpi (P = 0.021) compared to CTRL gilts (Figure 7D). However, given the percentage of T helper cells expressing CD8α increased significantly on 2 dpi (Figure 7E), the drop in total T helper cells on 2 dpi to 42% of the 0 dpi counts was over represented by the CD8α− phenotype, rather than the CD8α+ phenotype.Figure 7

Bottom Line: Our data also show a greater decrease of naïve B cells, T-helper cells and cytolytic T cells than their respective effector or memory counterparts.Absolute numbers of T cells and γδ T cells were negatively associated with PRRSv RNA concentration in gilt serum over time.Although many questions regarding the immune responses remain unanswered, these findings provide insight and clues that may help reduce the impact of PRRSv in pregnant gilts.

View Article: PubMed Central - PubMed

Affiliation: Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada. andrea.ladinig@vetmeduni.ac.at.

ABSTRACT
In spite of more than two decades of extensive research, the understanding of porcine reproductive and respiratory syndrome virus (PRRSv) immunity is still incomplete. A PRRSv infection of the late term pregnant female can result in abortions, early farrowings, fetal death, and the birth of weak, congenitally infected piglets. The objectives of the present study were to investigate changes in peripheral blood mononuclear cell populations in third trimester pregnant females infected with type 2 PRRSv (NVSL 97-7895) and to analyze potential relationships with viral load and fetal mortality rate. PRRSv infection caused a massive, acute drop in total leukocyte counts affecting all PBMC populations by two days post infection. Except for B cells, cell counts started to rebound by day six post infection. Our data also show a greater decrease of naïve B cells, T-helper cells and cytolytic T cells than their respective effector or memory counterparts. Absolute numbers of T cells and γδ T cells were negatively associated with PRRSv RNA concentration in gilt serum over time. Additionally, absolute numbers of T helper cells may be predictive of fetal mortality rate. The preceding three leukocyte populations may therefore be predictive of PRRSv-related pathological outcomes in pregnant gilts. Although many questions regarding the immune responses remain unanswered, these findings provide insight and clues that may help reduce the impact of PRRSv in pregnant gilts.

Show MeSH
Related in: MedlinePlus