Expression of CD80/CD86 and CTLA-4 mRNA in Peripheral Blood Mononuclear Cells of the Patients with Systemic Lupus Erythematosus

Summary: The role of CD80/CD86 and CTLA-4 in the pathogenesis of systemic lupus erythematosus and their clinical significance was investigated. By using RT-PCR technique, the expression of CD80/CD86 and CTLA-4 mRNA in peripheral blood mononuclear cells (PBMC) were semiquantitatively detected in 32 patients with active SLE. The results showed that the percentage of positive CD86 expression in active SLE was increased significantly as compared with normal controls (90.63 % vs 60.00 %, P<0.01). The mean level of CD86 mRNA expression in active SLE group was markedly higher than in the normal controls (0.6410+0.0174 vs 0.4510+0.0402, P<0.001). Compared with normal controls, the percentage of positive CTLA-4 expression and the mean level of CTLA-4 mRNA expression in active SLE group were both increased significantly (both P<0.01). There was no statistical differences in positive rate of CD80 and the average level of CD80 mRNA between the two groups (both P>0.05). It was concluded that the aberrant expression of CD86 and CTLA-4 might play an important role in the activity and development of SLE.

Impact of PRRSV on activation and viability of antigen presenting cells

Porcine reproductive and respiratory syndrome(PRRS) is one of the most important diseases of swine industry. The causal agent, PRRS-virus(PRRSV), is able to evade the host immune response and survive in the organism causing transient infections. Despite all scientific efforts, there are still some gaps in the knowledge of the pathogenesis of this disease. Antigen presenting cells(APCs), as initiators of the immune response, are located in the first line of defense against microorganisms, and are responsible for antigen recognition, processing and presentation. Dendritic cells(DCs) are the main type of APC involved in antigen presentation and they are susceptible to PRRSV infection. Thus, PRRSV replication in DCs may trigger off different mechanisms to impair the onset of a host effective immune response against the virus. On the one side, PRRSV may impair the basic functions of DCs by regulating the expression of major histocompatibility complex class Ⅱ and CD80/86. Other strategy followed by the virus is the induction of cell death of APCs by apoptosis, necrosis or both of them. The impairment and/or cell death ofAPCs could lead to a failure in the onset of an efficient immune response, as long as cells could not properly activate T cells. Future aspects to take into account are also discussed in this review.

An unbalanced PD-L1/CD86 ratio in CD14^＋＋CD16^＋ monocytes is correlated with HCV viremia during chronic HCV infection

Circulating monocyte subsets with distinct functions play important roles in hepatitis C virus （HCV） infection. However, the mechanisms have not been well studied. In this study, we analyzed the distributions and phenotypic characteristics of three circulating monocyte subsets--CD14^＋＋CD16^-, CD14^＋＋CD16^＋ and CD14^＋＋mCD16^——in chronic HCV-infected patients, HCV spontaneous resolvers and healthy controls, and we evaluated the possible link between HCV viremia and disease progression. Our results indicated that the frequency of the CD 14^＋＋CD 16^＋ monocyte subset was decreased, and negatively correlated with HCV RNA and core antigen levels during chronic HCV infection. PD-L1 expression and the PD-L1/CD86 ratio in CD14^＋＋CD16^＋ monocytes were higher during chronic HCV infection than in spontaneous HCV resolvers and healthy controls. The PD-L1/CD86 ratio positively correlated with HCV viral load and core antigen levels. Finally, PD-L1 was significantly increased, while cytokine secretions were dramatically decreased upon Toll-like receptor （TLR） ligand binding and HCV JFH-lstimulation. These findings indicates the compromised immune status of the CD14^＋＋CD16^＋ monocytes during chronic HCV infection and provides new insights into the specific role of the CD14^＋＋CD16^＋ monocytes and their significance in chronic HCV infection.

Neutrophils in Atlantic salmon(Salmo salar L.)are MHC class II^(+)and secret IL-12p40 upon bacterial exposure

Antigen-presentation via major histocompatibility complex(MHC)to T cells is the key event to initiate adaptive immune responses.In teleosts,as in mammals,the main types of professional antigen-presenting cells(APCs)are dendritic cells(DCs),monocytes/macrophages,and B cells.In the current study,flow cytometry,immunostaining and qPCR have been used to show that neutrophils in the teleost fish Atlantic salmon(Salmo salar L.)have antigen-presenting properties.The neutrophils were positive for MHC class II,CD83 and CD80/86,and upon in vitro bacterial exposure,gene expression analysis of purified neutrophils showed that IL-12p40,which is essential for proliferation of naïve T cells,was highly upregulated at both 6 and 24 h post bacterial exposure.Based on presence of MHC class II and upregulation of molecules involved in antigen presentation and T cell activation,we suggest that neutrophils in Atlantic salmon have potential to function as professional APCs.This work makes an important basis for further exploring the potential of using neutrophils to develop new,targeted immunoprophylactic measures.