Active and Passive Immunity. Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response. Artificially acquired active immunity can be induced by a vaccine, a substance that contains the antigen.
Lower back tightness can cause muscle twitching, pain and reduced range of motion. Lower back muscle tightness is the cause of a muscle spasm. This can be brought on by a strain, overuse or muscle weakness, according to BetterMedicine.com.
Emotional and physical stress can contribute muscles to tense and spasm causing soreness and pain. Muscle tightness may also happen due to the stiffness of muscles which is due to the inflammation of the muscles or joints. Obesity, diabetes, infections, hormonal balances can also cause inflammation of muscles leading to stiffness.