The role of scavenger receptor BI in hepatitis - eTheses Repository ...

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144 5.5 Adapted JFH-1 demonstrates an increased sensitivity to nAbs. Several reports have suggested that antibodies specific for the HCV gps neutralise viral infectivity by inhibiting HCV interaction(s) with CD81 (145, 147, 237)(reviewed in (295)). Given the increased binding of G451R E2 to CD81 we were interested to investigate the effects of this mutation on particle sensitivity to nAbs. We screened the sensitivity of JFH-1 wt and G451R virus to neutralisation by IgG purified from the sera of six HCV infected individuals. In each case G451R demonstrated an increased sensitivity to inhibition by patient IgG (Figure 5-7A-F). JFH-1 wt was inhibited to varying degrees by the patient IgG and in 5 of 6 cases the percentage neutralisation reached a plateau below 80%, suggesting that a population of particles were resistant to neutralisation. To quantify the increased sensitivity of G451R to antibody- dependent neutralisation, we determined the concentration of pooled HCV + patient IgG required to inhibit 50% of infectivity (inhibitory concentration, IC50). The IC50 for the wt and mutant viruses are 40µg/ml and 0.75µg/ml respectively, indicating that G451R is 50-fold more sensitive to neutralisation (Figure 5-7G). Patient derived IgG is polyclonal in nature and likely to target multiple conformation-dependent epitopes. To study virus neutralisation via a defined epitope we screened the sensitivity of both viruses to mAb 3/11, specific for E2 amino acids 412–423. G451R showed an increased sensitivity to 3/11 neutralisation (Figure 5-7H). These data are consistent with an increased sensitivity of G451R particles to nAbs targeting diverse epitopes, suggesting an increased availability of epitopes on G451R compared to the parental virus. However we failed to detect any difference in HCV + patient IgG or 3/11 binding to immobilised JFH-1 wt or G451R sE2 or to infected cells by
145 flow cytometry (data not shown), indicating that differential epitope presentation may only occur in the context of a virus particle.
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The role of scavenger receptor B-I
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i Abstract. With 170 million infect
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iii Acknowledgements. I would like
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v 5 Results: Identification of a re
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vii Figure 5-5 Analysis of JFH-1 wt
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1 Introduction 1.1 The disease. 1 D
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3 predominantly immuno-pathogenic i
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5 Aside from considerations of the
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7 Current attempts to design a HCV
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1.2 An elusive pathogen. 9 The emer
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11 PCR). This technique is highly s
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13 Within six years of the descript
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1.3 Basic virology. 15 Like other m
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17 Figure 1-2 HCV genome and polypr
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19 241). E1 and E2 are anchored to
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21 The characterisation of HCV geno
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23 in the E1 and E2 glycoprotein ge
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25 The solution reached by a great
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27 binding to mouse cells. sE2 inte
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29 density lipoprotein (HDL), allow
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31 blood brain barrier is permeable
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33 act as receptors for viral entry
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1.4.2 Attachment factors 35 The tru
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1.4.3 Endocytosis and fusion 37 Aft
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39 1.4.4 Co-receptor interplay and
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41 inhibition of protein kinase A (
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1.5 Lipoproteins 43 Since 1992 ther
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45 Lipoproteins exist in a dynamic
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47 and delivers its cargo via the w
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49 uptake of cholesterol from LDL (
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Figure 1-4 SR-BI-lipoprotein intera
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53 In summary the class B scavenger
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55 In 1992 Thomssen et. al. demonst
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57 lipoprotein association promotes
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59 Figure 1-5 Lipo-viro-particle as
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61 In vitro culture medium, into wh
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2 Materials and methods. 2.1 Cell l
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Preparation of rat anti-E2 mAbs. 65
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2.4 Basic techniques. Flow cytometr
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69 6. Finally, the cells were washe
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71 (Promega, WI, USA) kits accordin
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73 proteins and are incapable of fu
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75 spectrophotometer (Amersham), we
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77 Figure 2-2 Electroporated Huh-7.
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79 5. Data is expressed as percenta
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81 (Invitrogen). The samples to be
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83 1. The SR-BII coding region was
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2.7 Cloning and synthesis of JFH-1
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The sequence encoding amino acids 3
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Figure 2-6 sE2 sequencing. 89 JFH-1
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91 7. Large scale transfections wer
Page 103 and 104: 93 3 Results: Investigations using
Page 105 and 106: 95 3.2 CHO cells expressing human S
Page 107 and 108: Figure 3-3 Ability of anti-E2 mAb t
Page 109 and 110: 99 3.3 The interaction of sE2 with
Page 111 and 112: 101 Figure 3-5 Position of SR-BI mu
Page 113 and 114: 103 Table 3-2 Investigation of cell
Page 115 and 116: 105 3.4 Expression of SR-BII in CHO
Page 117 and 118: 3.5 Discussion. 107 We have demonst
Page 119 and 120: 109 may offer a tool to study the i
Page 121 and 122: 111 Figure 4-1A displays endogenous
Page 123 and 124: 113 4.2 Exogenous expression of SR-
Page 125 and 126: 115 4.3 Evidence of enhanced JFH-1
Page 127 and 128: 117 4.4 SR-BI expression levels lim
Page 129 and 130: 119 4.5 Murine SR-BI does not enhan
Page 131 and 132: 121 4.6 SR-BI/II expression levels
Page 133 and 134: 123 Figure 4-5 Over expression of S
Page 135 and 136: 125 Figure 4-6 Anti-SR-BI serum inh
Page 137 and 138: 127 Figure 4-7 Infection of Huh-7.5
Page 139 and 140: 129 cells is largely manifested in
Page 141 and 142: 131 5 Results: Identification of a
Page 143 and 144: 133 Figure 5-1 JFH-1 G451R has an a
Page 145 and 146: 135 Figure 5-2 CD81 dependence of J
Page 147 and 148: 137 G451R sE2 with hCD81 LEL we com
Page 149 and 150: 139 Figure 5-4 JFH-1 wt and G451R s
Page 151 and 152: 141 demonstrated a lower dependence
Page 153: 143 Figure 5-6 Relationship between
Page 157 and 158: 147 5.6 Low density JFH-1 particles
Page 159 and 160: 5.7 Discussion. 149 We have demonst
Page 161 and 162: 151 Numerous reports have used dens
Page 163 and 164: 153 demonstrate that low density JF
Page 165 and 166: 155 to over express SR-BI we were a
Page 167 and 168: 157 5-1), better able to engage CD8
Page 169 and 170: 159 Figure 6-1 An overview of antib
Page 171 and 172: 161 it is believed that ligation of
Page 173 and 174: 163 Given our and other’s finding
Page 175 and 176: 6.3 HCV lipo-viro-particles. 165 As
Page 177 and 178: 167 represent the hyper-variable re
Page 179 and 180: 169 The G451R mutation disrupts the
Page 181 and 182: 7 Bibliography 171 1. Acton, S., D.
Page 183 and 184: 173 include the CD81 tetraspanin an
Page 185 and 186: 175 receptor class B type I and inh
Page 187 and 188: 177 83. Drummer, H. E., K. A. Wilso
Page 189 and 190: 179 KewalRamani, D. R. Littman, C.
Page 191 and 192: 181 King. 1996. Efficient infection
Page 193 and 194: 183 hepatitis C virus envelope glyc
Page 195 and 196: 185 recovered chimpanzees exhibit r
Page 197 and 198: 187 218. Monazahian, M., I. Bohme,
Page 199 and 200: 189 243. Perez-Berna, A. J., J. Gui
Page 201 and 202: 191 single-cycle production assay t
Page 203 and 204: 193 298. Strickland, G. T., S. S. E
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195 Remaley, G. Csako, T. L. Eggerm
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197 2007. Scavenger receptor class
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