The immune system employs two key regulatory processes, positive and negative feedback, to manage immune responses and prevent harmful reactions. Positive feedback amplifies the response, enabling a strong reaction to infections. This can potentially result in chronic inflammation or autoimmune disorders if unchecked, so negative feedback mechanisms, primarily through Regulatory T cells, restrict and regulate responses, preserving healthy tissues. Maintaining a balance between these feedback mechanisms is crucial for an effective yet controlled immune response.

The immune system's cells communicate through various mechanisms ensuring an effective, coordinated response to pathogens. Key communication includes cytokines acting as messengers to regulate responses, chemokines guiding immune cells to infection sites, cell surface receptors initiating intracellular signaling, exosomes transferring information to other cells, and direct cell-to-cell contact facilitating signal and molecule transfer.

The cell-mediated innate immune system, which defends the host against pathogens, includes various cells. NK cells eliminate infected or abnormal cells, while macrophages and neutrophils engulf pathogens. Dendritic cells present antigens to T cells, initiating adaptive immune responses. Gamma-delta T cells provide quick immunity, and granulocytes detect and combat pathogens. Innate lymphoid cells, lacking antigen-specific receptors, contribute to early immune response.