Question

the initial insulin treatment for diabetes was problematic because it was causing allergic reactions in people. why was this?

the initial insulin was never mutated to ensure antigenic expression would match humans, while now the novel insulin is mutated to dampen antigen expression

the insulin was originally isolated from pigs and thus unfit for human treatment, while insulin now is purified from human donors to ensure no human rejection

the insulin was unpurified while humulin is properly purified and produced before being sold to diabetics

the insulin was taken from pigs and cows and hence triggered immune responses in humans due to the antigenic differences

Explanation:

Analyze the historical context of insulin

Early therapeutic insulin was extracted from the pancreases of slaughtered animals, primarily pigs (porcine) and cows (bovine). Although animal insulin is highly similar to human insulin, minor differences in their amino acid sequences exist.

Evaluate the immunological consequences

Because porcine and bovine insulins are foreign proteins, the human immune system can recognize them as non-self antigens. This antigenic difference frequently triggered allergic reactions and antibody production in diabetic patients.

Assess the given options

• Option 1 suggests mutating insulin to match humans, which is scientifically inaccurate regarding early extraction methods.
• Option 2 states modern insulin is purified from human donors, which is incorrect; modern insulin (Humulin) is produced using recombinant DNA technology in bacteria or yeast.
• Option 3 attributes the issue solely to purification, but even highly purified animal insulin can cause immune responses due to sequence differences.
• Option 4 correctly identifies that insulin was sourced from pigs and cows, and the resulting antigenic differences triggered human immune responses.

Answer:

• the initial insulin was never mutated to ensure antigenic expression would match humans, while now the novel insulin is mutated to dampen antigen expression
• the insulin was originally isolated from pigs and thus unfit for human treatment, while insulin now is purified from human donors to ensure no human rejection
• the insulin was unpurified while Humulin is properly purified and produced before being sold to diabetics
• the insulin was taken from pigs and cows and hence triggered immune responses in humans due to the antigenic differences (Correct answer)