The secondary immune response is one of the most important features of
immune systems. During the secondary immune response, the immune syst
em can eliminate the antigen, which has been encountered by the indivi
dual during the primary invasion, more rapidly and efficiently. Both T
and B memory cells contribute to the secondary response. In this pape
r, we only concentrate on the functions of memory B cells. We explore
a model describing the memory contributed by the specific long-lived c
lone which is maintained by continued stimulation with a small amount
of antigens sequestered on the surfaces of the follicular dendritic ce
lls (FDC). The behavior of the secondary response provided by the mode
l can be compared with experimental observations. The model shows that
memory B cells indeed play an important role in the secondary respons
e. It is found that a single memory cell in a long-lived clone may not
be long-lived. In the present note, the influences of relevant parame
ters on the secondary response are also explored.