Lactobacilli expressing variable domain of llama heavy-chain antibody fragments (lactobodies) confer protection against rotavirus-induced diarrhea.
BACKGROUND
Rotavirus-induced diarrhea poses a worldwide medical problem in causing substantial morbidity and mortality among children in developing countries. We therefore developed a system for passive immunotherapy in which recombinant lactobacilli constitutively express neutralizing variable domain of llama heavy-chain (VHH) antibody fragments against rotavirus.


METHODS
VHH were expressed in Lactobacillus paracasei, in both secreted and cell surface-anchored forms. Electron microscopy was used to investigate the binding efficacy of VHH-expressing lactobacilli. To investigate the in vivo function of VHH-expressing lactobacilli, a mouse pup model of rotavirus infection was used.


RESULTS
Efficient binding of the VHH antibody fragments to rotavirus was shown by enzyme-linked immunosorbent assay and scanning electron microscopy. VHH fragments expressed by lactobacilli conferred a significant reduction in infection in cell cultures. When administered orally, lactobacilli-producing surface-expressed VHH markedly shortened disease duration, severity, and viral load in a mouse model of rotavirus-induced diarrhea when administered both fresh and in a freeze-dried form.


CONCLUSIONS
Transformed lactobacilli may form the basis of a novel form of prophylactic treatment against rotavirus infections and other diarrheal diseases.
Pant
Neha
N
Division of Clinical Immunology, Department of Laboratory Medicine, Karolinska Institutet at Karolinska Huddinge, Stockholm, Sweden.
Hultberg
Anna
A
Zhao
Yaofeng
Y
Svensson
Lennart
L
Pan-Hammarstrom
Qiang
Q
Johansen
Kari
K
Pouwels
Peter H
PH
Ruggeri
Franco M
FM
Hermans
Pim
P
Frenken
Leon
L
Boren
Thomas
T
Marcotte
Harold
H
Hammarstrom
Lennart
L
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D002161:Camelids, New World / Q000276:immunology; D003967:Diarrhea / Q000517:prevention & control*; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000821:virology; D005822:Genetic Vectors; D007116:Immunization, Passive / Q000379:methods*; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D007778:Lactobacillus / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008855:Microscopy, Electron, Scanning; D011485:Protein Binding; D012401:Rotavirus / Q000276:immunology*; D012400:Rotavirus Infections / Q000517:prevention & control*
D000914:Antibodies, Viral; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region