For more on the meaning of colors for the color red. Orange is the color of social communication and optimism. From a negative color meaning it is also a sign of pessimism and superficiality. For more on the color orange. With the meaning of colors, in color psychology, yellow is the color of the mind and the intellect. It is optimistic and cheerful. However it can also suggest impatience, criticism and cowardice. For more on the color yellow.
The blood has several types of white blood cells including neutrophils, bands, eosinophils, basophils, monocytes and lymphocytes. Each fights infection in a different way. Neutrophils, for example, are one of the body's main defenses against bacteria. Neutrophils kill bacteria by ingesting them. Neutrophils can ingest five to 20 bacteria in their lifetime. Another type of white blood cell is called bands. Bands are immature neutrophils.
HIV attacks a specific subtype of white blood cells, the CD4 T cells. There are several different types of white blood cells, each of which is responsible for fighting specific types of infections (for example, viruses, bacteria, fungi, parasitic, etc.). CD4 T cells help the other types of white blood cells fight infection. When HIV infects a cell, it can survive there for many years, protected from antiviral medications. It slowly replicates, and its offspring infect other cells. Eventually, the virus takes over all of the cell functions in order to make more viral particles, leading to cell death.