What's the mechanism of immunological memory?

Immunological memory refers to the immune system's capacity to react faster and more efficiently to pathogens it has faced before. Immunological memory relies on a process called clonal selection. When the immune system encounters an antigen, B cells identify it using specialized antibodies on their surface. This triggers a rapid expansion of activated B cells, generating both plasma cells that produce antibodies for immediate defense and memory B cells that retain the ability to recognize the antigen for future encounters. If the same pathogen is encountered again, the immune system triggers a stronger and quicker response, aiding in efficient pathogen clearance and preventing disease development or severe illness. Memory cells, with their extended lifespan, persist within the body over time.