Cellule immunocompetenti.

Immune system fighting a cancer cell. A killer T-lymphocyte (orange) inducing a cancer cell to undergo Programmed Cell Death.
Human Body / immune system / macrophages & monocytes, Macrophages attacking parasite, SEM

SEM - White blood cells engulf spores of the fungus
SEM of a T-lymphocyte killer cell (small cell at left), attacking a large cancer tumour cell. The T- lymphocyte, a white blood cell, must make intimate contact with the tumour cell. It does so by recognizing antigens on the tumour’s surface.

Moving macrophage on the epithelial surface of the choroid plexus in the brain. The macrophage possess a ruffled cell border exhibiting thin cytoplasmic extensions that spread over the microvilli of the choroid epithelial cells. SEM **On Page Credit Required**

Peyer's patches (green), coloured scanning electron micrograph (SEM). These regions of lymphoid tissue are found in the human intestine, usually in the ileum, the final section of the small intestine.

Macrophage engulfing bacteria as part of the immune system's response to infection. SEM X9000

Antibodies and their antigen. Computer model showing the molecular structure of two anti-P-glycoprotein antibodies (upper left and right) and the P-glycoprotein (blue) to which they respond. These antibodies will bind to the glycoprotein, preventing it from functioning. ©Laguna Design/Science Source

A white blood cell attacking a pathogen.

Dendritic cell and lymphocyte, SEM
Phagocytosis. Coloured scanning electron micrograph (SEM) of a macrophage white blood cell (green) phagocytosing (engulfing) bacteria (yellow)

Neutrophil engulfing thrush fungus
 Immagini SEM di cellule immunocompetenti - fonte Pinterest