In immunology two types of immune response are described depending on whether there is prior contact with the antigen.
• At this first contact, only lymphocytes with receptors specific to the antigen in question are stimulated and lead to the production of antibodies capable of neutralizing it. The lymphocytes capable of recognizing a specific antigen are very few and the production of antibodies - of low intensity and limited duration - is detectable only after a period of latency of several days. This is called the primary response. The specificity of the resulting seropositivity, however, makes it possible to detect contamination (seroconversion).
• Upon re-contact with an antigen that has already triggered a primary response, specific antibody production is found to increase rapidly after a short latency period. The secretion of IgG then reaches levels much higher than those observed during the primary response, while that of IgM is of the same order. This early and intense response, called secondary response, most often results in the destruction of infectious agents before any clinical sign.
• Many centuries before the discovery of microbes, it was noted that people who developed a contagious disease without death were then specifically immunized against the disease, without being protected against others.
• The ability to react appropriately to an already received stimulus supposes the existence of a memory. The immune memory is based on the existence of memory B and T lymphocytes, resulting from the clonal expansion due to the first contact with the antigen. Their lifespan is significantly higher than that of other lymphocytes and their high reactivity gives its rapid and intense character to the secondary response.
Answer:
when the pores are completely filled in the rocks and soil
Explanation:
The zone of saturation is part of the divisions of ground water systems. It is the zone in which the pore spaces within the rock are completely filled with water.
The zone of saturation is where the aquifer lies in a body of water and it is the ground water prospect. Pore spaces can also be filled with hydrocarbons.
Above the zone of saturation is the water table. The water table defines the upper layer of the zone of saturation above which the pore spaces are filled with gas or no water can be found.
Answer:
Earth's magnetic field is created within Earth by the motion of liquid __________________ in Earth's _________________.
Explanation: iron; outer core
Answer: Piling up our waste in landfills affects the geosphere. Pumping waste into the oceans harms the hydrosphere. And overfishing and habitat destruction can reduce the diversity of living things in the biosphere.
Explanation: Hope this helps and good luck :)
Answer:
your answer is segmented body and exskostkeloton
Explanation:
I have did that question and got it right but the reasons why are there body is segmented in the ground and the exoskeleton is they don't have no skeleton except in there heads gl
