A monoclonal antibody specific for rat IL-18BP and its application in determining serum IL-18BP

Interleukin‑18 binding protein: Biological properties and roles in human and animal immune regulation (Review)

IL-18 binding protein (IL-18BP) is a natural regulatory molecule of the proinflammatory cytokine IL-18. It can regulate activity of IL-18 by high affinity binding. The present review aimed to highlight developments, characteristics and functions of IL-18BP. IL-18BP serves biological and anti-pathological roles in treating disease. In humans, it modulates progression of a number of chronic diseases, such as adult-onset Still's disease. The present review summarizes molecular structure, role of IL-18BP in disease and interaction with other proteins in important pathological processes.

A novel approach for rapid high-throughput selection of recombinant functional rat monoclonal antibodies

Background

Most monoclonal antibodies against mouse antigens have been derived from rat spleen-mouse myeloma fusions, which are valuable tools for purposes ranging from general laboratory reagents to therapeutic drugs, and yet selecting and expressing them remains a time-consuming and inefficient process. Here, we report a novel approach for the rapid high-throughput selection and expression of recombinant functional rat monoclonal antibodies with different isotypes.

Results

We have developed a robust system for generating rat monoclonal antibodies through several processes involving simultaneously immunizing rats with three different antigens expressing in a mixed cell pools, preparing hybridoma cell pools, in vitro screening and subsequent cloning of the rearranged light and heavy chains into a single expression plasmid using a highly efficient assembly method, which can decrease the time and effort required by multiple immunizations and fusions, traditional clonal selection and expression methods. Using this system, we successfully selected several rat monoclonal antibodies with different IgG isotypes specifically targeting the mouse PD-1, LAG-3 or AFP protein from a single fusion. We applied these recombinant anti-PD-1 monoclonal antibodies (32D6) in immunotherapy for therapeutic purposes that produced the expected results.

Conclusions

This method can be used to facilitate an increased throughput of the entire process from multiplex immunization to acquisition of functional rat monoclonal antibodies and facilitate their expression and feasibility using a single plasmid.

Electronic supplementary material

The online version of this article (10.1186/s12865-018-0274-8) contains supplementary material, which is available to authorized users.

The effects of IL-18BP on mRNA expression of inflammatory cytokines and apoptotic genes in renal injury induced by infrarenal aortic occlusion

BACKGROUND

Renal injury is an important complication of infrarenal aortic occlusion (IAO), which is mainly encountered during the postoperative period. Aortic clamping procedure may lead to turbulent blood flow and eventually vasoconstriction at renal arterial level of the abdominal aorta. IL-18BP has well-known antioxidant and anti-inflammatory properties. In this study, we aimed to determine whether IL-18BP has anti-inflammatory, antiapoptotic, antioxidant, and protective effects on acute kidney damage induced by IAO rat model.

MATERIALS AND METHODS

A total of 30 adult male Wistar-Albino rats were equally and randomly separated to three groups as follows: SHAM laparotomy, ischemia-reperfusion (IR), and IR + IL-18BP. We applied 30-min IAO and 2-h reperfusion. Inflammatory cytokine levels (TNF-α, IL-1β, IL-18, IL-6, and IFN-γ) and oxidative stress parameters (TAS, TOS, and OSI) were measured. In addition to this, urea and creatinine levels, histopathology of kidney, mRNA expression levels of inflammatory cytokines, and apoptotic genes were investigated.

RESULTS

Urea and creatinine, tissue and serum levels of TNF-α, IL-6, IL-18, IFN-γ, and TOS, and oxidative stress index (OSI) were found significantly lower in IR + IL-18BP group, when compared to the IR group. Moreover, mRNA expression levels of inflammatory cytokines and apoptotic genes were prominently depressed in IR + IL-18BP pre-treatment group in histopathologic examination, there was a significant difference between the IR and other three groups (P < 0.001). These improvements were demonstrated with a total score of histopathologic damage. In our previous studies, we have demonstrated that IL-18BP has antioxidant, inflammatory, and protective effects on liver and spinal cord IR injury. Data established from the present study suggest that IL-18BP may exert anti-inflammatory, antiapoptotic, antioxidant, and protective effects on IAO-induced acute kidney injury in rats, and this would be the first study to be conducted in this field.

CONCLUSIONS

Data established from the present study suggest that IL-18BP may exert anti-inflammatory, antiapoptotic, antioxidant, and protective effects on IAO-induced acute kidney injury in rats.

Monoclonal antibodies directed against the outer membrane protein of Bordetella avium

Bordetella avium is the etiologic agent of coryza and rhinotracheitis in poultry. This respiratory disease is responsible for substantial economic losses in the poultry industry. Monoclonal antibodies (MAbs) were produced against the outer membrane proteins (OMPs) of B. avium isolated from diseased chickens. BALB/c mice were immunized with the extracted B. avium OMPs. Then the splenocytes from immunized mice and SP2/0 myeloma cells were fused using PEG 4000. Three stable hybridoma clones (designated as 3G₁₀, 4A₃, and 4E₈) were produced via indirect ELISA and three rounds of subcloning. The MAbs were classified as IgG1, and can recognize the 58  kDa OMP band by Western blot assays. No MAb cross-reactivity with chicken Proteus mirabilis, Escherichia coli, and Salmonella was observed. A double antibody sandwich ELISA (DAS-ELISA) was developed using the rabbit polyclonal antibodies as the capture antibody and MAb 4A₃ as the detection antibody. Under the DAS-ELISA, the minimum detectable concentration of B. avium was 1 × 10(4) CFU/mL, and no cross-reactivity occurred with chicken Proteus mirabilis, Escherichia coli, and Salmonella. Results showed that the DAS-ELISA has good sensitivity and specificity. Clinical application showed the DAS-ELISA was more sensitive than the plate agglutination test. This study may be used to develop a quick and specific diagnostic kit, analyze epitopes, and establish systems for typing B. avium.

Development and characterization of monoclonal antibody against non-structural protein-2 of Chikungunya virus and its application

The recent epidemics of Chikungunya viruses (CHIKV) with unprecedented magnitude and unusual clinical severity have raised a great public health concern worldwide, especially due to unavailability of vaccine or specific therapy. This emphasizes the need to understand the biological processes of this virus in details. Although CHIKV associated research has been initiated, the availability of CHIKV specific reagents for in-depth investigation of viral infection and replication are scanty. For Alphavirus replication, non-structural protein 2 (nsP2) is known to play a key regulatory role among all other non-structural proteins. The current study describes the development and characterization of nsP2 specific monoclonal antibody (mAb) against a synthetic peptide of CHIKV. Reactivity and efficacy of this mAb have been demonstrated by ELISA, Western blot, Flow cytometry and Immunofluorescence assay. Time kinetic study confirms that this mAb is highly sensitive to CHIKV-nsP2 as this protein has been detected very early during viral replication in infected cells. Homology analysis of the selected epitope sequence reveals that it is conserved among all the CHIKV strains of different genotypes, while analysis with other Alphavirus sequences shows that none of them are 100% identical to the epitope sequence. Moreover, using the mAb, three isoforms of CHIKV-nsP2 have been detected in 2D blot analysis during infection in mammalian cells. Accordingly, it can be suggested that the mAb reported in this study can be a sensitive and specific tool for experimental investigations of CHIKV replication and infection.

Characterization of monoclonal antibodies against goat interleukin-18 and their application in the measurement of goat interleukin-18 in LPS-stimulated peripheral blood mononuclear cells by sandwich ELISA

In order to develop a specific assay for the measurement of goat IL-18 level, two stable hybridoma cell lines were established which secreted IgG1 monoclonal antibodies (mAbs) against goat IL-18. Specific binding of two mAbs named 2E8 and 4C4 to recombinant goat IL-18 expressed in Escherichia coli was demonstrated in an ELISA and Western blotting. Results also showed that mAbs 2E8 and 4C4 bound to distinct epitopes in the ELISA additivity test. These two mAbs were applied in IFA analysis for the detection of goat IL-18 expressed in 293FT cells and in the sandwich ELISA for the measurement of goat IL-18 levels in LPS-stimulated PBMC. Results from this study demonstrated that mAbs against goat IL-18 recognize bovine and human IL-18 and could be used to measure IL-18 levels in different inflammations or immune responses in future studies.