Final answer:
The type of immunity involving specialized cells directly attacking foreign substances is Cellular immunity. This is managed by T cells as part of the adaptive immune system and contrasted with B cells which are associated with humoral immunity.
Step-by-step explanation:
The type of immunity that involves a direct attack of the foreign substance by specialized cells of the immune system is B. Cellular immunity. This form of immunity is part of the adaptive immune system and relies on T cells that are directed against intracellular pathogens. B cells, in contrast, are part of humoral immunity and release antibodies that fight pathogens in extracellular spaces.
As part of the cell-mediated immune response, T cells come in various types, including helper, cytotoxic, and regulatory T cells, which play a role in the destruction of infected cells or cancer cells. This is essential for clearing out pathogens that have managed to enter host cells, where they are largely protected from the antibodies of the humoral immune response. The adaptive immune system is highly specific to an invading pathogen and is capable of developing long-term memory to protect the host from future reinfections with the same type of pathogen.