During the course of a pathogen infection, the detection of pathogen-specific IgM antibodies in a patient's acute-phase serum serves the purpose of early diagnosis. Typically, two ELISA formats are employed for the detection of human IgM antibodies: the indirect human IgM ELISA (Fig. 1) and the human IgM capture ELISA (Fig. 2). Our project team offers mouse anti-human IgM monoclonal antibodies specifically designed for use in these assays—designated as MAb0040 and HRP0040 for the indirect human IgM ELISA, and as MAb0035 and MAb0038 for the human IgM capture ELISA.

Fig.1 Schematic Diagram of the Indirect ELISA for Human IgM.

Fig. 2. Schematic diagram of the human IgM capture ELISA.

This batch of monoclonal antibodies (MAbs) consists of hybridoma antibodies generated by immunizing mice with purified human IgM antibody protein. The heavy and light chain isotypes for MAb0040 are γ2a/κ, while those for MAb0035 and MAb0038 are γ2b/κ and γ1/κ, respectively. This batch of MAbs specifically binds to the human IgM heavy chain (μ); it exhibits no cross-reactivity with human IgG, IgA, or IgE, nor with human antibody light chains (κ or λ) (Fig. 3). 

Fig.3 Cross-reactivity of MAbs 0040, 0038, and 0035 with human IgG, IgA, and IgE.

MAb0040 serves as the enzyme-labeled secondary antibody in the indirect ELISA system for human IgM (Fig. 1). This monoclonal antibody demonstrates the advantages of low background noise and a high signal-to-noise ratio (Tab. 1), making it suitable for the early diagnosis of infectious diseases in the acute phase.

Tab.1 OD450nm readings of human negative sera in the MAb0040-mediated indirect ELISA for human IgM (using COVID-19 as an example). All human sera were diluted 1:100. PC: Positive Control; Blk: Blank Control. Cutoff = 0.258.

Mouse Anti-Human μ Heavy Chain Monoclonal Antibodies (MAb0040, HRP0040, MAb0035, MAb0038)