Corrigendum to ‘Efficient generation of monoclonal antibodies from single human B cells by single cell RT-PCR and expression vector cloning’[J. Immunol. Methods 329 (2008) 112−124]

Preparation and Evaluation of the Fully Humanized Monoclonal Antibody GD-mAb Against Respiratory Syncytial Virus

Respiratory syncytial virus (RSV) is the major cause of pulmonary and bronchial inflammation in infants, young children, and immunocompromised adults, but therapeutic options to control RSV are limited. In the present study a single chain antibody against RSV (GD-scFv) was screened using phage display library panning technology and a full-length monoclonal antibody (GD-mAb) was developed from GD-scFv based on the sequence encoding Ig V_H and Ig V_L. The anti-RSV potential of GD-mAb was evaluated in vitro and in mice. Our results indicated that both GD-scFv (4.25 ± 2 nM) and GD-mAb (3.13 ± 0.89 nM) showed high binding capability and strong binding specificity to GD protein. GD-mAb effectively neutralized RSV and reduced the plaque number in a concentration-dependent manner through a plaque reduction neutralization assay. In mice, GD-mAb lowered the lung index and reduced the lung virus titer in the mouse lung (p < 0.05). Antibody treatment reduced the phosphorylated protein level in pathways of TLR4/NF-κB, MAPKs, and PI3K/Akt (p < 0.05) and correlated with an absence of pro-inflammatory factors TNF-α, IL-1β, and IL-6 in the mouse lung and serum (p < 0.05). In summary, these data suggest that GD-mAb may be an effective therapeutic agent for the treatment of RSV infections.

Importance 

Currently, only a few therapeutic options are available to control respiratory RSV in humans. In this study, our group developed a full-length monoclonal antibody (GD-mAb) and reported a high binding specificity of the RSV surface glycoproteins G. Moreover, GD-mAb effectively neutralized RSV in vitro, and significantly lowered the lung index and reduced the lung virus titer in an infected mouse lung, which suggests that GD-mAb may serve as an effective antiviral agent for RSV infection.

An antigen-specific, four-color, B-cell FluoroSpot assay utilizing tagged antigens for detection

The FluoroSpot assay, a variant of ELISpot utilizing fluorescent detection, has so far been used primarily for assessment of T cells, where simultaneous detection of several cytokines has allowed a more qualitative analysis of functionally distinct T cells. The potential to measure multiple analytes also presents several advantages when analyzing B cells. Our aim was to develop a B-cell FluoroSpot assay adaptable to studies of a variety of antigens. The assay utilizes anti-IgG antibodies immobilized in 96-well filter membrane plates. During cell culture, IgG antibodies secreted by antibody-secreting cells (ASCs) are captured in the vicinity of each of these cells and the specificity of single ASCs is defined using antigens for detection. The antigens were labeled with biotin or peptide tags enabling secondary detection with fluorophore-conjugated streptavidin or tag-specific antibodies. The assay, utilizing up to four different tag systems and fluorophores simultaneously, was evaluated using hybridomas and immunized splenocytes as ASCs. Assay variants were developed that could: i) identify multiple ASCs with different antigen specificities; ii) detect ASCs showing cross-reactivity with different but related antigens; and iii) define the antigen-specificity and, by including anti-IgG subclass detection reagents, simultaneously determine the IgG subclass of antibodies secreted by ASCs. As demonstrated here, the B-cell FluoroSpot assay using tag-based detection systems provides a versatile and powerful tool to investigate antibody responses by individual cells that can be readily adapted to studies of a variety of antigen-specific ASCs.