Immunization of rabbits with highly purified, soluble, trimeric human immunodeficiency virus type 1 envelope glycoprotein induces a vigorous B cell response and broadly cross-reactive neutralization.
Previously we described induction of cross-reactive HIV-1 neutralizing antibody responses in rabbits using a soluble HIV-1 gp140 envelope glycoprotein (Env) in an adjuvant containing monophosphoryl lipid A (MPL) and QS21 (AS02A). Here, we compared different forms of the same HIV-1 strain R2 Env for antigenic and biophysical characteristics, and in rabbits characterized the extent of B cell induction for specific antibody expression and secretion and neutralizing responses. The forms of this Env that were produced in and purified from stably transformed 293T cells included a primarily dimeric gp140, a trimeric gp140 appended to a GCN4 trimerization domain (gp140-GCN4), gp140-GCN4 with a 15 amino acid flexible linker between the gp120 and gp41 ectodomain (gp140-GCN4-L), also trimeric, and a gp140 with the flexible linker purified from cell culture supernatants as either dimer (gp140-L(D)) or monomer (gp140-L(M)). Multimeric states of the Env proteins were assessed by native gel electrophoresis and analytical ultracentrifugation. The different forms of gp140 bound broadly cross-reactive neutralizing (BCN) human monoclonal antibodies (mAbs) similarly in ELISA and immunoprecipitation assays. All Envs bound CD4i mAbs in the presence and absence of sCD4, as reported for the R2 Env. Weak neutralization of some strains of HIV-1 was seen after two additional doses in AS02A. Rabbits that were given a seventh dose of gp140-GCN4-L developed BCN responses that were weak to moderate, similar to our previous report. The specificity of these responses did not appear similar to that of any of the known BCN human mAbs. Induction of spleen B cell and plasma cells producing immunoglobulins that bound trimeric gp140-GCN4-L was vigorous, based on ELISpot and flow cytometry analyses. The results demonstrate that highly purified gp140-GCN4-L trimer in adjuvant elicits BCN responses in rabbits accompanied by vigorous B cell induction.
Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Gerald V
GV
Quinnan
Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Olusegun
O
Onabajo
Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Pengfei
P
Zhang
Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Lianying
L
Yan
Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Joseph J
JJ
Mattapallil
Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Zhiqiang
Z
Zhang
Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Ming
M
Dong
Department of Microbiology and Molecular Genetics, Public Health Research Institute, New Jersey Medical School, Newark, New Jersey, United States of America.
Min
M
Lu
Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America.
David
D
Montefiori
Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America.
Celia
C
LaBranche
Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
Christopher C
CC
Broder
D000276:Adjuvants, Immunologic; D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology*; D000917:Antibody Formation / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D003429:Cross Reactions / Q000276:immunology*; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D015483:HIV Antibodies / Q000276:immunology*; D015488:HIV Antigens / Q000276:immunology; D006801:Humans; D007114:Immunization; D008198:Lymph Nodes / Q000276:immunology / Q000378:metabolism; D009500:Neutralization Tests; D011485:Protein Binding; D055503:Protein Multimerization; D011817:Rabbits; D019713:Receptors, CCR5 / Q000378:metabolism; D013154:Spleen / Q000276:immunology / Q000378:metabolism; D054299:env Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism
D000276:Adjuvants, Immunologic; D057134:Antibodies, Neutralizing; D018985:Epitopes, B-Lymphocyte; D015483:HIV Antibodies; D015488:HIV Antigens; D019713:Receptors, CCR5; D054299:env Gene Products, Human Immunodeficiency Virus; C097729:gp140 envelope protein, Human immunodeficiency virus 1