Both A3- and A8-specific T cells are HLA-DR-restricted CD4+ T cells.

<p>(A) and (B) PBMCs from adult donors were stimulated with A3 or A8 peptides and then expanded with recombinant IL-2. (A) The stimulated PBMCs were stained with fluorescently labeled antibodies against CD3, CD4, CD8 and IFNγ before flow cytometric analysis. Antigen-specific IFNγ production was primarily associated with CD4+ T cells. (B) CD8+ T cells produced negligible level of IFNγ in response to A3 or A8. (C) A3 and A8 can induce strong CD4+ cell responses in HFMD patients infected by EV71. (D) and (E) ELISpot assays were performed to examine IFNγ production by PBMCs which were stimulated with A3 (D) or A8 (E) peptides alone or in presence of blocking antibodies against HLA-DR, HLA-DP, or HLA-A, B and –C (HLA-ABC). The results were shown as average spot forming units ± standard deviation (n = 3). Only anti-HLADR antibodies abrogated the ELISpot responses, demonstrating that the responses to EV71 are Class II-restricted.</p

EV71 A3 or A8-specific CD4+ T cells respond to the poliovirus 3 Sabin (PV3) homolog, A3v peptide.

<p>PBMCs from two adult subjects were cultured in the presence of EV71 A3, EV71 A8, PV3 A3v, or SP4 peptides for 4 days and then with recombinant human IL-2 for additional 3 days. The cells were washed and re-stimulated with SP4, EV71 A3 or PV A3′, then surface-stained with fluorescent antibodies against CD3 and CD4 molecules and intracellularly for the production of IFNγ. Gated CD3+ cells are shown. (A) SP4 or PV3 A3v-stimulated cells were re-stimulated with the respective peptides. (B) EV71 A3-stimulated cells were re-stimulated with SP4, EV71 A3 or PV3 A3v, respectively. (C) EV71 A8-stimulated cells were re-stimulated with SP4, EV71 A8 or PV3 A3v, respectively. The above results were representative data from three independent experiments.</p

The Cytokine and Chemokine Profiles in Patients with Hand, Foot and Mouth Disease of Different Severities in Shanghai, China, 2010

<div><p>Background and purpose</p><p>Systemic upregulation of inflammatory cytokines is characteristic of critical severe hand, foot, and mouth disease (HFMD) with pulmonary edema. Thus, immunomodulatory medicines such as steroids, including methylprednisolone, have been proposed to treat patients with severe HFMD in China, because it is postulated that inflammatory cytokines play a role in the development of severe complications. This study is to further investigate the inflammatory response in the relatively mild HFMD patients, and whether steroid treatment has a beneficial effect on the suppression of inflammation in HFMD patients.</p><p>Method</p><p>We measured the levels of 50 kinds of chemokines, cytokines, growth factors and soluble receptors in serum samples from control patients without HFMD and the HFMD patients with or without prior treatment of intravenous methylprednisolone.</p><p>Results</p><p>Our present study found that even relatively mild HFMD patients without central nervous system (CNS) complications had elevated serum levels of inflammatory cytokines, including interleukin (IL)-3, IL-6, IL-12p40, and tumor necrosis factor (TNF)-α, which suggested systemic inflammation. In contrast, these patients also have decreased levels of other serum biomarkers, including IL-1Ra, IL-8, IL-16, soluble ICAM-1, CXCL-1, and CCL27. The dysregulation of cytokine and chemokine expression may be involved in CNS complications and unbalanced circulating leukocytes in HFMD patients. Surprisingly, patients treated with methylprednisolone had no difference in the expression levels of HFMD-associated biomarkers instead had slightly increased levels of IL-17A, which was not associated with the occurrence of HFMD.</p><p>Conclusion</p><p>Whether steroid treatment has any beneficial effect on the prognosis of HFMD patients requires to be further investigated.</p></div

The correlation between host biomarkers and disease prognosis.

<p>Levels of CCL27 (A), CXCL1 (B), and soluble VCAM-1 (C) in serum samples obtained from control patients (Ctrl, n = 20) and HFMD patients with or without CNS complications (n = 20, respectively). The line represents the average value. (D) Plots of soluble VCAM-1 concentrations in sera of HFMD patients against their maximal fever temperatures. Numbers above square brackets indicate P values for the corresponding comparisons.</p

Immune biomarkers whose levels in serum samples of HFMD patients were significantly different from those of control patients.

*<p>Significance was analyzed via Student's <i>t</i>-test and P values were further adjusted with the Benjamini-Hochberg procedure.</p

TLR3 Signaling in Macrophages Is Indispensable for the Protective Immunity of Invariant Natural Killer T Cells against Enterovirus 71 Infection

<div><p>Enterovirus 71 (EV71) is the most virulent pathogen among enteroviruses that cause hand, foot and mouth disease in children but rarely in adults. The mechanisms that determine the age-dependent susceptibility remain largely unclear. Here, we found that the paucity of invariant natural killer T (iNKT) cells together with immaturity of the immune system was related to the susceptibility of neonatal mice to EV71 infection. iNKT cells were crucial antiviral effector cells to protect young mice from EV71 infection before their adaptive immune systems were fully mature. EV71 infection led to activation of iNKT cells depending on signaling through TLR3 but not other TLRs. Surprisingly, iNKT cell activation during EV71 infection required TLR3 signaling in macrophages, but not in dendritic cells (DCs). Mechanistically, interleukin (IL)-12 and endogenous CD1d-restricted antigens were both required for full activation of iNKT cells. Furthermore, CD1d-deficiency led to dramatically increased viral loads in central nervous system and more severe disease in EV71-infected mice. Altogether, our results suggest that iNKT cells may be involved in controlling EV71 infection in children when their adaptive immune systems are not fully developed, and also imply that iNKT cells might be an intervention target for treating EV71-infected patients.</p></div

Dynamic Changes of the Hemagglutination-Inhibition Titers against the Seasonal H1N1 Virus after Administration of the 2009 A/H1N1 Influenza Vaccine.

<p>Dynamic Changes of the Hemagglutination-Inhibition Titers against the Seasonal H1N1 Virus after Administration of the 2009 A/H1N1 Influenza Vaccine.</p

ELISA to detect specific anti-HA IgG antibody at different time points in the sera of volunteers for the 2009 A/H1N1 influenza vaccine administration.

<p>The OD450 nm on different days were measured and results were displayed as ΔOD450 nm with each prevaccination (baseline) OD subtracted in every subject's serial samples. "pre": pre-vaccination. The OD value of the pre-vaccination sera was 0.76±0.06 (IgG baseline). The blank OD (no sera added) of the ELISA was 0.05. **: p<0.001, two-way Student's t-test.</p

Geometric Mean HI Titers against the 2009 A/H1N1 Influenza Virus in Two Groups of People with Different Seasonal Influenza Antibody Levels.

†<p>Individuals with prevaccination seasonal influenza HI titer ≥1∶40.</p><p>° Individuals with prevaccination seasonal influenza HI titer <1∶40.</p><p>*(p<0.05) and</p><p>**(p<0.001) represent the statistical differences between the two groups, two-way Student's t-test.</p

Dynamic Changes of the Hemagglutination-Inhibition Titers against the 2009 A/H1N1 Virus after Administration of the 2009 A/H1N1 Influenza Vaccine.

<p>Seroprotection is defined as HI titer of 1∶40 or more. Seroconversion is defined as postvaccination HI titer of 1∶40 or more, increasing at least four times. GMT = geometric mean titer. HI titers below 1∶10 were assigned a value of 1∶5, in calculating the geometric mean titer.</p><p>*(p<0.05) and</p><p>**(p<0.001) represent the statistical significances compared with the pre-vaccination values (day 3 value for seroconversion rate). The Pearson's chi-squared test was used for the seroprotection and seroconversion rate analysis, the two-way Student's t-test for the GMT analysis. Pre: pre-vaccination.</p