Lymph is a fluid that circulates throughout the body in the lymphatic system. It forms when tissue fluids/blood plasma (mostly water, with proteins and other dissolved substances) drain into the lymphatic system. It contains a high number of lymphocytes (white cells that fight infection).
Puppies normally get their first shots around 8 weeks old, but they can be given earlier if needed (ie with stray, abandoned pups or those who were formula fed). Three sets of combination vaccinations (a shot that protects against more than one disease) given at 3 week intervals. 8 weeks - first round.
You puppy will need additional vaccinations after his first shots. Your vet will determine the exact schedule, but typically these booster shots are given every two to four weeks until the pup is about 16 weeks old.