Which of the following is classified as killer, helper, regulator, and memory cells?

A. Serum sickness is the correct answer. It is a type III hypersensitivity reaction that can occur when the body reacts to proteins in animal-derived immune serum, often used in treatments like antitoxins or antivenoms. Symptoms may include rash, fever, joint pain, and swelling.
B. Rejection syndrome typically refers to the immune system's rejection of transplanted organs or tissues, not a response to serum.
C. Kaposi sarcoma is a cancer associated with human herpesvirus 8 (HHV-8), most commonly seen in immunocompromised individuals, such as those with AIDS. It is unrelated to immune serum reactions.
D. Hay fever (allergic rhinitis) is an allergic reaction to airborne substances like pollen, not to animal-derived serum

A. Transfer through the placenta or breast milk is a form of naturally acquired passive immunity, where antibodies are passed from mother to child without the child's immune system having to produce them.
B. Inflammation is part of the innate immune response and not related to passive immunity.
C. Vaccination with an antigen involves stimulating the body to produce its own immune response, which is active immunity, not passive.
D. Administration of antiserum provides artificially acquired passive immunity, where pre-formed antibodies are given to an individual for immediate protection.
E. Tears and saliva are part of the innate immune system (first line of defense) and are not considered forms of passive immunity.