Editing Immune system (section)

=== Immunological memory ===
{{further|Immunity (medical)}}
When B cells and T cells are activated and begin to replicate, some of their offspring become long-lived memory cells. Throughout the lifetime of an animal, these memory cells remember each specific pathogen encountered and can mount a strong response if the pathogen is detected again. T-cells recognize pathogens by small protein-based infection signals, called antigens, that bind directly to T-cell surface receptors.<ref>Sauls RS, McCausland C, Taylor BN. Histology, T-Cell Lymphocyte. In: StatPearls. StatPearls Publishing; 2023. Accessed November 15, 2023. http://www.ncbi.nlm.nih.gov/books/NBK535433/</ref> B-cells use the protein, immunoglobulin, to recognize pathogens by their antigens.<ref>	Althwaiqeb SA, Bordoni B. Histology, B Cell Lymphocyte. In: StatPearls. StatPearls Publishing; 2023. Accessed November 15, 2023. http://www.ncbi.nlm.nih.gov/books/NBK560905/</ref> This is "adaptive" because it occurs during the lifetime of an individual as an adaptation to infection with that pathogen and prepares the immune system for future challenges. Immunological memory can be in the form of either passive short-term memory or active long-term memory.{{sfn | Sompayrac | 2019 | p=98}}