Vaccines, disease, mab

• A vaccine is a suspension of antigens intentionally put into the body to induce artificial active immunity
• Two main types of vaccines are live attenuated and inactivated
• Vaccinations can be administered by injection or orally
• Vaccinations produce long-term immunity by creating memory cells that remember the antigen when reencountered, leading to a faster, stronger secondary response
• Live attenuated vaccines contain whole pathogens that have been 'weakened', while inactivated vaccines contain whole pathogens that have been killed or small parts of the pathogens
• Herd immunity arises when a sufficiently large proportion of the population has been vaccinated, making it difficult for a pathogen to spread within that population
• Eradicating disease through vaccines can be challenging due to various factors such as unstable political situations, lack of public health facilities, and the complexity of certain pathogens
• Active immunity is acquired when an antigen triggers a specific immune response, while passive immunity is acquired without an immune response
• In active immunity, memory cells are produced, providing long-term immunity and a faster, stronger secondary response upon reencountering the same pathogen
• Passive immunity is acquired without an immune response, and antibodies are not produced by the infected person
• Artificial passive immunity occurs when people are given an injection or transfusion of antibodies, while natural passive immunity occurs when foetuses receive antibodies across the placenta from their mothers or babies receive antibodies through breast milk
• Babies receive antibodies across the placenta from their mothers
• Babies receive the initial breast milk from mothers (colostrum) which delivers a certain isotype of antibody (IgA)
• Active immunity is when the body produces antibodies, while in passive immunity the body is given the antibodies
• HIV, Human Immunodeficiency Virus, is a retrovirus that is spread by intimate human contact and can only be transmitted by direct exchange of body fluids
• The structure of the HIV virus includes two RNA strands, proteins (including reverse transcriptase enzyme), a protein coat (capsid), a viral envelope with a lipid bilayer and glycoproteins, and attachment proteins
• When HIV enters the bloodstream, it infects helper T cells, uses their cell machinery to multiply, and gradually reduces the number of helper T cells in the immune system
• Symptoms of AIDS, the disease caused by HIV, include mild flu-like symptoms initially, followed by a gradual destruction of helper T cells, leading to decreased immune response and susceptibility to opportunistic diseases
• Monoclonal antibodies have diagnostic uses such as in pregnancy tests, diagnosing HIV, detecting pathogens, blood typing, and locating blood clots
• Ethical issues with vaccines and monoclonal antibodies include concerns about animal testing, use of animal-based substances, and risks involved in human trials
• Therapeutically, monoclonal antibodies are used in treating diseases like rabies, preventing organ rejection, autoimmune therapies, and targeted cancer treatments
• Substances are sometimes used in the production of vaccines, but some people disagree with this
• Even at the human-trial stage, a vaccine carries a small risk, and volunteers may be at higher risk of contracting the disease if they mistakenly believe the trial vaccine will fully protect them
• Human volunteers in vaccine trials are often paid, but ethical issues can arise if volunteers feel pressured due to financial status
• Some people refuse vaccines due to the small possibility of side effects, but herd immunity often protects them
• Ethical issues around monoclonal antibody therapies often revolve around animal rights issues
• Claims about vaccines need scientific validation, involving repeated studies and evaluation of data and methodology
• The MMR vaccine study in 1998 with a small sample size suggested a link to autism, but a larger study in 2005 in Japan showed no such link
• ELISA tests can be used to see if a patient has antibodies to a certain antigen or any antigens to a certain antibody
• Direct ELISA tests use a single antibody that is complementary to the antigen being tested for, while indirect ELISA tests use two different antibodies (primary and secondary antibodies)
• Indirect ELISA tests can be used to test for antibodies or antigens, such as for HIV or prostate cancer