which bsl level is for lethal agents for which there are no vaccines or other countermeasures
Biosafety level Biosafety level 4 (BSL-4) is the highest level of biosafety precautions, and is appropriate for work with agents that could easily be aerosol-transmitted within the laboratory and cause severe to fatal disease in humans for which there are no available vaccines or treatments.[8] BSL-4 laboratories are generally set up to be either cabinet laboratories or protective-suit laboratories.[8] In cabinet laboratories, all work must be done within a class III biosafety cabinet.[8] Materials leaving the cabinet must be decontaminated by passing through an autoclave or a tank of disinfectant.[8] The cabinets themselves are required to have seamless edges to allow for easy cleaning. Additionally the cabinet and all materials within must be free of sharp edges in order to reduce the risk of damage to the gloves.[8] In a protective-suit laboratory, all work must be done in a class II biosafety cabinet by personnel wearing a positive pressure suit.[8] In order to exit the BSL-4 laboratory, personnel must pass through a chemical shower for decontamination, then a room for removing the positive-pressure suit, followed by a personal shower.[8] Entry into the BSL-4 laboratory is restricted to trained and authorized individuals, and all persons entering and exiting the laboratory must be recorded.[8]
Adaptive immune system Unlike the innate immune system, the adaptive immune system is highly specific to a particular pathogen. Adaptive immunity can also provide long-lasting protection; for example, someone who recovers from measles is now protected against measles for their lifetime. In other cases it does not provide lifetime protection; for example, chickenpox. The adaptive system response destroys invading pathogens and any toxic molecules they produce. Sometimes the adaptive system is unable to distinguish harmful from harmless foreign molecules; the effects of this may be hayfever, asthma or any other allergy. Antigens are any substances that elicit the adaptive immune response. The cells that carry out the adaptive immune response are white blood cells known as lymphocytes. Two main broad classes—antibody responses and cell mediated immune response—are also carried by two different lymphocytes (B cells and T cells). In antibody responses, B cells are activated to secrete antibodies, which are proteins also known as immunoglobulins. Antibodies travel through the bloodstream and bind to the foreign antigen causing it to inactivate, which does not allow the antigen to bind to the host.[1]