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Delayed acquisition of Plasmodium falciparum antigen-specific CD4(+) T cell responses in HIV-exposed uninfected Malawian children receiving daily cotrimoxazole prophylaxis.

Longwe H, Phiri KS, Mbeye NM, Gondwe T, Mandala WL, Jambo KC - Malar. J. (2016)

Bottom Line: P. falciparum antigen-specific CD4(+) T cells responses were measured by intracellular cytokine staining assay.There were no differences in the proportions of naïve, effector and memory CD4(+) T cell subsets between HEU and HUU children at all ages.There was a trend showing acquisition of P. falciparum-specific IFN-γ and TNF-producing CD4(+) T cells with age in both HUU and HEU children.

View Article: PubMed Central - PubMed

Affiliation: Department of Basic Medical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi. herbert.longwe@gmail.com.

ABSTRACT

Background: Cotrimoxazole (CTX) prophylaxis, recommended in HIV-exposed uninfected (HEU) children primarily against HIV-related opportunistic infections, has been shown to have some efficacy against Plasmodium falciparum malaria. The effects of CTX prophylaxis on the acquisition of P. falciparum antigen specific CD4(+) T cells-mediated immunity in HEU children is still not fully understood.

Methods: Peripheral blood was collected from HEU and HIV-unexposed uninfected (HUU) children at 6, 12 and 18 months of age. Proportion of CD4(+) T cells subsets were determined by immunophenotyping. P. falciparum antigen-specific CD4(+) T cells responses were measured by intracellular cytokine staining assay.

Results: There were no differences in the proportions of naïve, effector and memory CD4(+) T cell subsets between HEU and HUU children at all ages. There was a trend showing acquisition of P. falciparum-specific IFN-γ and TNF-producing CD4(+) T cells with age in both HUU and HEU children. There was, however, lower frequency of P. falciparum-specific IFN-γ-producing CD4(+) T cells in HEU compared to HUU at 6 and 12 months, which normalized 6 months after stopping CTX prophylaxis.

Conclusion: The results demonstrate that there is delayed acquisition of P. falciparum-specific IFN-γ-producing CD4(+) T cells in HEU children on daily cotrimoxazole prophylaxis, which is evident at 6 and 12 months of age in comparison to HUU age-matched controls. However, whether this delayed acquisition of P. falciparum-specific IFN-γ-producing CD4(+) T cells leads to higher risk to malaria disease remains unknown and warrants further investigation.

No MeSH data available.


Related in: MedlinePlus

Representative FACS plots showing gating strategy for identifying antigen specific CD4+ T cell by intracellular cytokine staining assay. Heparinized whole blood collected at 6, 12 and 18 months was stimulated with PMA, P. falciparum 3D7 strain, purified protein derivative (PPD) and no antigen for 24 h. Lymphocytes were gated using FSC vs. SSC plots, FSC vs. CD3+ T cells and then CD4+T cells vs. CD8+T cells to isolate CD4+ T cells. Non-stimulated control samples were used to establish the threshold quadrants of background responses that were applied to quantify positive cytokine-producing cells in paired antigen-stimulated samples
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Fig2: Representative FACS plots showing gating strategy for identifying antigen specific CD4+ T cell by intracellular cytokine staining assay. Heparinized whole blood collected at 6, 12 and 18 months was stimulated with PMA, P. falciparum 3D7 strain, purified protein derivative (PPD) and no antigen for 24 h. Lymphocytes were gated using FSC vs. SSC plots, FSC vs. CD3+ T cells and then CD4+T cells vs. CD8+T cells to isolate CD4+ T cells. Non-stimulated control samples were used to establish the threshold quadrants of background responses that were applied to quantify positive cytokine-producing cells in paired antigen-stimulated samples

Mentions: Immune phenotypic defects have been previously reported in HEU infants, mostly in the pre-ART era [28], but it still remains unclear whether this is the case during the ART era. This study, therefore, phenotypically characterized CD4+ T cell subsets in HEU children and HUU aged-matched controls, to investigate whether HIV exposure and CTX prophylaxis alters the population of CD4 T cell subsets in children. The expression of CD45RA and CCR7 allowed for the characterization of naïve (CD45RA+CCR7+), central memory (TCM, CD45RA−CCR7+), effector memory (TEM, CD45RA−CCR7−), and terminally differentiated (CD45RA+CCR7−) T cells (Fig. 1a). There were no significant differences in the median proportion of naïve CD4+ T cells (Fig. 1b), TCM CD4+T cells (Fig. 2c), TEMCD4+ T cells (Fig. 2d) and terminally differentiated CD4+ T cells (Fig. 2e) between HEU and HUU children at all ages (6, 12 and 18 months). These data suggest that HIV exposure or probably CTX prophylaxis did not lead to any apparent impairment in the populating of CD4+ T cell subsets beyond 6 months of age in HEU children.Fig. 1


Delayed acquisition of Plasmodium falciparum antigen-specific CD4(+) T cell responses in HIV-exposed uninfected Malawian children receiving daily cotrimoxazole prophylaxis.

Longwe H, Phiri KS, Mbeye NM, Gondwe T, Mandala WL, Jambo KC - Malar. J. (2016)

Representative FACS plots showing gating strategy for identifying antigen specific CD4+ T cell by intracellular cytokine staining assay. Heparinized whole blood collected at 6, 12 and 18 months was stimulated with PMA, P. falciparum 3D7 strain, purified protein derivative (PPD) and no antigen for 24 h. Lymphocytes were gated using FSC vs. SSC plots, FSC vs. CD3+ T cells and then CD4+T cells vs. CD8+T cells to isolate CD4+ T cells. Non-stimulated control samples were used to establish the threshold quadrants of background responses that were applied to quantify positive cytokine-producing cells in paired antigen-stimulated samples
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4862093&req=5

Fig2: Representative FACS plots showing gating strategy for identifying antigen specific CD4+ T cell by intracellular cytokine staining assay. Heparinized whole blood collected at 6, 12 and 18 months was stimulated with PMA, P. falciparum 3D7 strain, purified protein derivative (PPD) and no antigen for 24 h. Lymphocytes were gated using FSC vs. SSC plots, FSC vs. CD3+ T cells and then CD4+T cells vs. CD8+T cells to isolate CD4+ T cells. Non-stimulated control samples were used to establish the threshold quadrants of background responses that were applied to quantify positive cytokine-producing cells in paired antigen-stimulated samples
Mentions: Immune phenotypic defects have been previously reported in HEU infants, mostly in the pre-ART era [28], but it still remains unclear whether this is the case during the ART era. This study, therefore, phenotypically characterized CD4+ T cell subsets in HEU children and HUU aged-matched controls, to investigate whether HIV exposure and CTX prophylaxis alters the population of CD4 T cell subsets in children. The expression of CD45RA and CCR7 allowed for the characterization of naïve (CD45RA+CCR7+), central memory (TCM, CD45RA−CCR7+), effector memory (TEM, CD45RA−CCR7−), and terminally differentiated (CD45RA+CCR7−) T cells (Fig. 1a). There were no significant differences in the median proportion of naïve CD4+ T cells (Fig. 1b), TCM CD4+T cells (Fig. 2c), TEMCD4+ T cells (Fig. 2d) and terminally differentiated CD4+ T cells (Fig. 2e) between HEU and HUU children at all ages (6, 12 and 18 months). These data suggest that HIV exposure or probably CTX prophylaxis did not lead to any apparent impairment in the populating of CD4+ T cell subsets beyond 6 months of age in HEU children.Fig. 1

Bottom Line: P. falciparum antigen-specific CD4(+) T cells responses were measured by intracellular cytokine staining assay.There were no differences in the proportions of naïve, effector and memory CD4(+) T cell subsets between HEU and HUU children at all ages.There was a trend showing acquisition of P. falciparum-specific IFN-γ and TNF-producing CD4(+) T cells with age in both HUU and HEU children.

View Article: PubMed Central - PubMed

Affiliation: Department of Basic Medical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi. herbert.longwe@gmail.com.

ABSTRACT

Background: Cotrimoxazole (CTX) prophylaxis, recommended in HIV-exposed uninfected (HEU) children primarily against HIV-related opportunistic infections, has been shown to have some efficacy against Plasmodium falciparum malaria. The effects of CTX prophylaxis on the acquisition of P. falciparum antigen specific CD4(+) T cells-mediated immunity in HEU children is still not fully understood.

Methods: Peripheral blood was collected from HEU and HIV-unexposed uninfected (HUU) children at 6, 12 and 18 months of age. Proportion of CD4(+) T cells subsets were determined by immunophenotyping. P. falciparum antigen-specific CD4(+) T cells responses were measured by intracellular cytokine staining assay.

Results: There were no differences in the proportions of naïve, effector and memory CD4(+) T cell subsets between HEU and HUU children at all ages. There was a trend showing acquisition of P. falciparum-specific IFN-γ and TNF-producing CD4(+) T cells with age in both HUU and HEU children. There was, however, lower frequency of P. falciparum-specific IFN-γ-producing CD4(+) T cells in HEU compared to HUU at 6 and 12 months, which normalized 6 months after stopping CTX prophylaxis.

Conclusion: The results demonstrate that there is delayed acquisition of P. falciparum-specific IFN-γ-producing CD4(+) T cells in HEU children on daily cotrimoxazole prophylaxis, which is evident at 6 and 12 months of age in comparison to HUU age-matched controls. However, whether this delayed acquisition of P. falciparum-specific IFN-γ-producing CD4(+) T cells leads to higher risk to malaria disease remains unknown and warrants further investigation.

No MeSH data available.


Related in: MedlinePlus