number of unique antibodies in blood
size of antibody repertoire
size of B cell population
number of B cells in lymphocyte population

I made a bionumbers page of this
-http://bionumbers.hms.harvard.edu/bionumber.aspx?&id=110381

-10^10. . ."At any given time, the serum antibody repertoire of an individ-
ual contains ~1010 antibody speci?cities consisting of basal levels
of low af?nity near germline antibody clones, along with af?nity
matured clones that re?ect an individual’s immunological history."
--A general method for characterization of humoral immunity induced by a vaccine or infection
-10^11. . ."The
combinatorial association of such stochastically generated light and
heavy chains has the potential to generate many orders of magni-
tude more diversity than can be uniquely displayed on the 10 11
B-cells in a single individual’s lymphocyte population (2,8)"
--this quote is from this paper: "Precise determination of the diversity of a combinatorial antibody library gives insight into the human antibody repertoire"
--reference 2 is to "Theoretical studies of clonal selection Minimal antibody and reliability of self-non-self discrimination", but from a quick scan I did not find the 10^11 number
--reference 8 "Number and distribution of lymphocytes in man" seems to be inaccessible.  Perhaps it is too old (1974 or something) and it is from Germany


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See also
 -[Number of Immunoglobulin G molecules in 1 ml of serum]
 -[How many antibodies are in the body_]