““The way immunity works is that one's immune system initially learns about a new pathogen when antigen presenting cells (APCs) carry an antigen (fragment of a pathogen) back to your B memory cells, which live in your lymph system. The APC also tells you B cell where it found the antigen. An antigen could be a spike protein, or some other protein in/on the virus, or it could be something else like an oligosaccharide. Each B cell that receives an APC with a payload will try to construct an antigen-specific immunoglobulin (antibody) that should match that antigen fragment. Those antibodies will have two prongs that can grab the pathogen by that fragment, and they will have one opposing prong that will bind to any of several passing immune cells, such as T cells, which will destroy the antibody and its payload.”

The immune system does learn about new pathogens through antigen-presenting cells (APCs), but APCs primarily present antigens to T cells, not directly to B memory cells. APCs such as dendritic cells, macrophages, and B cells process and present antigen fragments on MHC molecules to activate T cells.cwoer.ccbcmd.educwoer.ccbcmd.eduThe Adaptive Immune System: Antigen-Presenting Cells (APCs)library.fiveable.melibrary.fiveable.meAntigen-Presenting Cells (APCs) - (Anatomy and Physiology I)+2 more

B memory cells reside in lymphoid tissues but are not the primary recipients of antigen presentation by APCs. Instead, B cells can recognize native antigens directly via their B cell receptors (BCRs) without requiring APC presentation. The process described where APCs 'tell' B cells where they found the antigen is not supported by immunological evidence.

Antigens can indeed be proteins such as viral spike proteins or other molecular structures like oligosaccharides; this part is accurate.

The description that each B cell tries to construct an antigen-specific antibody after receiving an APC payload is incorrect. B cells generate a diverse repertoire of antibodies through gene rearrangement independently of APC input. Upon encountering their specific antigen, B cells become activated and differentiate into plasma cells producing antibodies.

The statement that antibodies have 'two prongs' that grab the pathogen and 'one opposing prong' that binds to immune cells such as T cells which then destroy the antibody and its payload is inaccurate. Antibodies are Y-shaped molecules with two antigen-binding sites (Fab regions) and one Fc region. The Fc region can bind Fc receptors on various immune effector cells (including some T cell subsets indirectly), facilitating pathogen clearance but not destruction of the antibody itself.

T cells do not destroy antibodies; rather, they help coordinate immune responses. Cytotoxic T cells kill infected host cells presenting antigen, while helper T cells assist B cell activation.