Compartmentalization of the IgG immune response to HIV-1 in breast milk.
OBJECTIVE
To evaluate the IgG immune response to HIV-1 in colostrum.


METHODS
Paired serum and colostrum were collected from 16 asymptomatic HIV-1-infected women. IgG to gp160 and to four peptides (gp41 immunodominant DI domain, gp41/Id; EDLKWA epitope of DIII domain, gp41/K; gp120 C-terminus, gp120/Ct; V3 loop, gp120/V3) were evaluated in all samples. Functional activity of purified IgG was assessed for the ability to block transcytosis of cell-associated HIV-1 through a tight monolayer of endometrial epithelial cell line HEC1.


RESULTS
IgG antibody to gp160 and to the four env-encoded synthetic peptides were detected in all specimens. The mean specific activity of IgG to gp41/K was 4.2 fold higher in colostrum than in paired serum. In contrast, mean specific activities of IgG to gp160 and gp41/Id were twofold higher in serum than in paired colostrum. Mean specific activities of IgG to gp120/V3 and to gp120/Ct were similar in systemic and milk compartments. Functional activity of IgG was evaluated in six paired serum and colostrum: in two women, serum IgG was 3.0 and 7.6 fold more efficient in blocking transcytosis than colostrum IgG; in one patient, colostrum IgG exhibited a 28 fold higher inhibitory capacity than serum IgG; in the remaining patients, serum and colostrum IgG demonstrated similar inhibitory activities against transcytosis of HIV.


CONCLUSIONS
These features are consistent with a compartmentalization of the humoral IgG immune response to HIV within the mammary gland. Some HIV-1 antigens are able to induce a strong humoral mucosal immune response which may be of relevance for the design of a mucosal vaccine against HIV-1.
Becquart
P
P
Unité INSERM U430, Hôpital Broussais, Paris, France.
Hocini
H
H
Garin
B
B
Sépou
A
A
Kazatchkine
M D
MD
Bélec
L
L
D000293:Adolescent; D000328:Adult; D000818:Animals; D001942:Breast Feeding; D002478:Cells, Cultured; D003126:Colostrum / Q000276:immunology; D004705:Endocytosis / Q000187:drug effects; D000939:Epitopes; D005260:Female; D015483:HIV Antibodies / Q000032:analysis* / Q000097:blood; D015488:HIV Antigens / Q000276:immunology; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000276:immunology; D019302:HIV Envelope Protein gp160 / Q000276:immunology; D015700:HIV Envelope Protein gp41 / Q000276:immunology; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology* / Q000502:physiology; D006801:Humans; D018928:Immunity, Mucosal; D007074:Immunoglobulin G / Q000032:analysis* / Q000097:blood / Q000276:immunology; D008895:Milk, Human / Q000276:immunology*; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology* / Q000821:virology
D000939:Epitopes; D015483:HIV Antibodies; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; D019302:HIV Envelope Protein gp160; D015700:HIV Envelope Protein gp41; C059762:HIV envelope protein gp120 (305-321); D007074:Immunoglobulin G; D010446:Peptide Fragments