Is there any particular reason for choosing this age group? What if older mice were used in immunization study?
I agree with Jonathan. They have good immune responses, are easy to handle, and are sexually mature around this age. Depending on the literature, older mice will be considered aged (I've seen at early as 6 months and upwards) and will exhibit reduced immune responses (typically anyway). Furthermore, while you don't have to use mice right away at 6-8 wk, it just helps to reduce costs to use mice as soon as possible.
There's likely some wiggle room to play with the age for immunization, but you must also factor in the time following immunization for assessment of the immune response and potentially challenge of the mice to evaluate protection.
Immunization of mice suppose the easy route of injection of the test product , maturity of the immune system and the ability to harvest products for the control of the reaction to the product : measurement of antibodies produced , or immunocompetent cells or others).
Another frequently used parameter is the weight of the mice. Generally, mice are used whose weight varies between 18 and 22 g .
Is there any article saying about immunological age in mice?
the issue of weight mentioned. by Brahimi depends a lot on the mouse strain used, the weights mentioned are NOT useful for all the strains. I agree with previous comments that i) 6-8 weeks old mice have a mature immune system, ii) it is cheaper, since we use pay a per week free at the animal facilities to use 6-8 weeks old mice is preferred to 6-8 months old mice, and iii) you should take into account the immunisation pattern you want to use, if it is long, you do not want to get the animals too old....
Besides, it is possible to immunise effectively 6-8 months old mice. Regarding the question of Camila dealing with the immune response at different ages, I am not aware of any article dealing with it.
