Which of the following statement is correct about the immunity? Statement 1: Innate responses occur rapidly and can generate effector mechanisms that are effective within minutes or hours of infection.  Statement 2: Adaptive immunity takes much longer to become effective, usually over a few days. 

Which of the following statement is correct about the immunity? Statement 1: Innate responses occur rapidly and can generate effector mechanisms that are effective within minutes or hours of infection.  Statement 2: Adaptive immunity takes much longer to become effective, usually over a few days.  Correct Answer Both 1 & 2

The correct answer is 3 i.e. Both 1 & 2.

Host defense: 

• All organisms possess mechanisms to defend themselves against infection, and immunity is a specialized form of host defense. 
• In mammals, defense mechanisms can be passive or active. 
• Passive defense comes in the form of natural barriers that hinder infection. 
• Examples are skin, which prevents access of microbes to the underlying tissue, and gastric acid in the stomach which, not surprisingly, can kill many microbes that might be ingested with food. 
• Their existence is quite independent of the presence of infection. 
• Active defense is brought about by immune responses that involve a diversity of different effector mechanisms that are induced by the presence of infection and which may eliminate the microbe. 
• Thus, all forms of active immunity depend on specific recognition of molecules present in the infecting agent. 
• This in turn leads to a response, involving the interaction of cells and molecules to produce different effector mechanisms that can often eliminate the infection.
• Immunity is itself divided into two different forms – innate and adaptive. 
• Innate responses occur rapidly and can generate effector mechanisms that are effective within minutes or hours of infection. 
• In contrast, adaptive immunity takes much longer to become effective, usually over a few days. 
• In immunity to most forms of infection, however, both innate and adaptive immunity are essential. 
• A major advantage of adaptive immune responses, not seen with innate immunity, is that they generate memory – a second infection with the same microbe elicits a stronger, faster, and usually more effective response.