Immune checkpoints can be stimulatory or inhibitory. IL-4 has dual effects upon macrophage biological function, which may be either stimulatory or inhibitory. CTLA4 transmits an inhibitory signal to T cells, whereas CD28 transmits a stimulatory signal. He developed a detailed immune network theory based on symmetrical stimulatory, inhibitory and killing interactions. Estrogen and progesterone inhibit the stimulatory effects of prolactin on milk production. LOS is highly stimulatory to the human immune system. During the process, influx of glucose ensures sufficient ATP to sustain the stimulatory effect. This indicates that cmvIL-10 may lack the stimulatory effects that hIL-10 has on these cells. This activates a protein, called a G-protein (s for stimulatory). In fact, lack of further stimulatory signals sends the T cell into anergy. Light is inhibitory to zoospore formation but stimulatory to zoospore germination.